Abstract
The Proactive Crime Scene Response is a technique utilizing targeted forensic analytical results to guide criminal investigations in real time. Analytical value of evidence maximized by forensic laboratories is directly related to the recognition, documentation, collection, and preservation of evidentiary items located at the crime scene. Improved education, coordination and communication between the crime scene investigators and forensic scientist experts creates a seamless analytical process flow, enabling greater focus on high value evidence with decreased response time and greater impact on investigational direction. Real time data from focused forensic analyses and use of databases provides primary investigative leads, with suspect identities, whereabouts at the time of crime commission, links to other crimes and other critical collaborative crime solving information. Case examples highlighting successful application of various aspects of this model will be provided, with recommendations for implementation including Rapid DNA and supporting business cases.
Keywords: Proactive crime scene response, Crime scene, Forensic laboratory, Backlog, Tiered analysis, Focused analysis, Rapid DNA, Business case
1. Introduction
In the current forensic service delivery model, law enforcement is responsible for immediately attending the crime scene, protecting public safety by making it safe. Once the risk to person and property has passed, particularly for major cases of crimes against persons, specialized personnel with crime scene training and experience are then called to crime scenes. Their role is to attend to a secure crime scene, recognizing and documenting evidence, then collecting, and preserving it. Some preliminary processing and analysis may take place in situ, such as developing latent prints, and screening for biological materials or controlled dangerous substances. In many jurisdictions, evidence may be taken to a secondary secure location where evidence can be dried and sampled, under more favorable and controlled environmental conditions. Field tests may be applied such as a screening or presumptive test, however more specific confirmatory tests are ideally left to forensic laboratories accredited to forensic standards with specialized scientific staff. Instruments such as Rapid DNA are bringing greater speed, sensitivity and specificity to screening tests, however at present, confirmation by forensic scientist experts working in an accredited forensic laboratory remains a nearly universal requirement for forensic analysis admissible in judicial proceedings. As case circumstances evolve and become clearer, specialized investigators are assigned, such as detectives for major crimes, who will in turn conduct more extensive interviews and investigations. Items of evidence may be submitted to the forensic laboratory for forensic analysis by first responding police personnel, crime scene specialists, specialized investigators, or detectives, depending on the crime and local policies guiding forensic evidence submission and analysis.
In many current models, there is segmentation between the crime scene investigators, frequently staffed by field-based law enforcement personnel, and forensic laboratory staff, typically staffed by career forensic scientist experts located in a permanent forensic laboratory building. This separation of duties and locations causes forensic laboratories to be inherently reactive in nature, applying scientific procedures to maximize the value of evidence when called upon once a submission to the laboratory has occurred. Forensic laboratories are generally unaware of specific crimes until after this request for analysis is made, which can occur some time after the crime has been committed. As forensic evidence is perishable, that is its value diminishes over time, the utility of forensic data wanes as the span of time between commission of crime and analysis grows. After submission of evidence and request for analysis, depending on the backlog at the forensic laboratory, analysis will commence after the case has made its way to the front of the waiting line.
Many forensic laboratories seek to minimize the operational impact of a backlog of cases awaiting analysis to commence by prioritizing cases and triaging submissions. Taking cases out of the order of submission can provide a quick response for an individual item or case, however a rush case bumps other cases, pushing them back in the queue, thereby lengthening their response time. With high priority cases jumping the queue, lower priority cases are inevitably delayed, reducing the opportunity for offenders to be identified in lesser crimes prior to escalation to more dangerous ones. Triaging case items relies upon accurate and timely information regarding the investigation, which can be challenging to ascertain, particularly if considerable time has elapsed since a crime was committed and contact is delayed by investigative personnel working a variety of shifts. While investigators can reach out to the forensic laboratory at any time to advocate for their case and request specific analyses, such efforts are frequently reserved for high priority cases.
Recent articles make the case that backlogs at forensic laboratories are a symptom of inadequate resources [[1], [2], [3]]. There is also evidence that the cost to society of backlogs of cases awaiting analysis to start in terms of increased cost of crime is far greater than the additional resources to eliminate those backlogs [3]. Other authors propose the distinction of forensic science as a discipline unto itself, to create greater coordination on a centralized purpose rather than technique-based examinations [4]. Sufficient forensic resources that permit a consistent rapid response would result in a revolutionary positive change in effectiveness of investigation by developing and eliminating suspects quickly and conclusively as a regular course of business without disrupting the flow of analysis. While elected and high-ranking officials responsible for public safety and investigation of crime tend to the chore of balancing resources to optimize response times and clearance rates, forensic laboratory managers responsible for the forensic enterprise must focus on what can be done to optimize existing resources in the interim.
Backlogs of cases awaiting analysis to be started have an impact beyond the analytical resources required to address the immediate cases themselves. Backlogged cases serve to bog down the entirety of analytical capacity, as resources are taken to manage the pile rather than focus on providing analysis itself. Every effort that is not conducting casework removes resources from backlog reduction. Providing an expedited response on a small subset of evidentiary items can do more than provide pivotal investigative information to investigators. That quick answer can direct efforts away from redundant and wasteful analyses focused on the wrong suspect or the wrong line of analysis. Every redundant analysis conducted on the case at hand is an analysis that cannot be conducted on the next most important case waiting in line.
Eliminating analytical backlogs requires more than just resources of staff, instrumentation, consumables and laboratory space; they require training and implementation of accreditation components to put analytical capacity in place. Acting proactively to focus existing forensic expertise on high value evidence is a strategy which can optimize resource use immediately. Whether resources are lacking to eliminate backlogs, are in the process of being requested, obtained, or put into place, forensic laboratories must support crime scene investigators not only with the best analytical results, but also furnish information and education to obtain the evidence that produces it. Through providing a quick response on very narrowly targeted items, more accurately directed investigations are made more efficient and effective, thereby potentially negating more extensive requests for analysis.
2. The problem statement
In the absence of forensic evidence, investigations are frequently driven by eye-witness testimony. While witness statements can often be substantiated by others’ testimony, investigations that are without suspects are particularly jeopardized without supporting analytical results. Evidence is perishable and can deteriorate while it awaits analysis. A suspect who is beyond apprehension is still at large to commit new crimes on new victims, negatively impacting public safety. Unsolved crimes likewise create fear in communities and increase the likelihood of miscast suspicion and wrongful accusation and conviction. As forensic evidence is backed by objective data, development of suspects based on data should be front end loaded into investigations, rather than awaiting time in line in a forensic laboratory backlog. The problem and a potential solution presented here can be defined as: How can we best recognize and prioritize critical evidence items to drive investigations with objective data?
3. Issue discussion
GIGO is the abbreviation of garbage in, garbage out, which can also be alternated to read good in, good out if one chooses to focus on the positive [5]. The GIGO abbreviation originates from the world of computer science. It is used to say that if the quality of the data put into a computer is low, the quality of the information produced from that data is low [5]. The mission of the forensic laboratory is to maximize the value of evidence [1]. The analysis provided by the forensic laboratory is only as good as the evidence that is collected. One cannot make a quality chicken salad from chicken feathers. Hence, focusing on improving the quality of initial evidence from the crime scene will enable the highest investigative value to be generated by forensic laboratories. Providing timely education and support for recognition, collection and preservation of crime scene evidence is critically important to obtaining the best evidence in the best condition for forensic scientists to work with. If pertinent evidence is overlooked and not collected its potential value to directing the investigation is not realized.
Investigative resources are front end loaded. This means that the largest quantity of resources is expended at the beginning of the investigation, as a suspect is developed [1]. When a suspect is not immediately apparent, without a timely forensic investigative lead, investigations suffer from a lack of speed. Finding key items (needle) while not wasting time on less valuable items (haystack) is a key to a quicker investigative response as well as a quicker forensic laboratory response time. A solution to streamline crime scene recognition and selection of critical items is to facilitate a rapid forensic laboratory response on small subset of crime evidence. Through focusing resources and prioritizing analysis on high value evidentiary items over those less likely to provide probative results or are duplicative, enables provision of scientific support in real time. Prioritizing analysis of a short list of key items reduces time in analysis and reporting, so investigations can focus resources on the correct suspects more quickly. Not only is public safety and efficacy a benefactor, but protection of individual rights, including those potentially wrongfully suspected.
Forensic analytical flows frequently utilize a 2-step screening and confirmation model. Less specific analyses are conducted first, with information gained directing more complex but more specific confirmation testing. Some analyses such as field drug testing have moved screening tests outside the walls of the forensic laboratory. Advances in forensic technology including the use of large databases of known samples have shown the potential of NIBIN (National Integrated Ballistic Information Network) and Rapid DNA to provide quick screening results, with confirmation of results to occur at the forensic laboratory. This extension of traditional forensic analyses outside of the traditional brick and mortar forensic laboratory represents an opportunity to provide quicker access to timely results to direct investigations.
The current service delivery model with segregation between the forensic laboratory non-sworn forensic scientist experts and law enforcement largely sworn staff presents several challenges. The quickly advancing pace of technology is a challenge for both forensic laboratories and law enforcement. Forensic laboratories must identify, investigate, and evaluate new technology. Once technology is obtained, extensive validation must demonstrate instruments and methodology are fit for purpose, before it can be applied to evidentiary samples. Validation is mandated as a requirement for accredited forensic laboratories, also necessary for access to the National DNA Index System (NDIS). Once technology is validated and implemented, investigative agents , crime scene personnel and submitting agencies must be informed and educated to properly recognize, document, collect, preserve, and submit evidence in light of new technologically enabled capabilities.
Non-sworn forensic scientist experts often stay within their original forensic discipline (e.g., Toxicology, Drug Chemistry, DNA, Latent Prints, Trace, Firearms, etc.) or forensic laboratory for the entirety of their career. Staff attending crime scenes are frequently sworn personnel. Irregular hours and rigors of crime scene demands increases potential for staff turnover, as do opportunities for promotion outside of the crime scene unit. Sworn personnel frequently limit their career and advancement opportunities if they stay in one role past 3–5 years. Specific training for each particular type of crime scene evidence and its potential through analysis may be measured in hours or days, compared to months or years for forensic scientist experts. Forensic laboratories often serve a wide variety of law enforcement and investigative departments, small and large, many without dedicated crime scene response personnel. Forensic scientist experts perform specialized analyses for many agencies, gathering extensive experience in their area of expertise. Many crime scene response personnel may also be assigned several other roles, and hence do not have the luxury of focusing only on crime scene training and responsibilities. Hence, there is potentially a disparity of continuity, expertise, and experience between forensic scientist experts and specialists attending crime scenes.
The nature of crime scene response is very challenging. A wide variety of scenarios present themselves in all manner of situations, locations, and environments. Crime scenes can exist indoors or outdoors, in all climates and weather. Personal communication with a colleague from Africa indicated that two crime scene personnel investigating a plane crash “were taken by lions.” While many crime scenes present dangers they are thankfully not usually this extreme in the United States. Crime scene investigators do often have only one opportunity to collect evidence at the crime scene, as search warrants span a limited timeframe and scenes cannot be held for infinite periods of time. Therefore, there is a natural tendency toward over-collection of evidence, particularly when case information is limited at the early stages of a case investigation. This natural overcollection in turn has the potential to hamper the flow of evidence and analysis if investigators and forensic staff are not empowered to make decisions to limit analysis to probative items of evidence. If everything is important, nothing is important.
In ideal circumstances, resources required to conduct forensic analysis are matched to the demand for analysis, enabling all cases to be analyzed as they are submitted. Where resources are inadequate, analytical backlogs develop. While cases sit awaiting analysis in a backlog, the Proactive Crime Scene Response can be taken to provide the benefit of quick targeted analysis of selected high value items. A downside of this approach is that cases are bumped back in the analytical queue and the smooth flow of analysis is disrupted, thereby reducing overall productivity. Not all jurisdictions have the luxury of affording sufficient resources across all analytical disciplines, or resources have been allocated and are in the process of being built and staff trained. This approach can be taken as an interim step on the path toward optimal service for all cases, where no cases are expedited at the expense of other cases.
4. Method
A Proactive Crime Scene Response program is proposed to provide an expedited response including dedicated forensic scientist experts to support key investigations with rapid forensic analyses to develop or eliminate suspects in hours or days. Objective scientific data provided by forensic analysis drives investigations very cost effectively [[1], [2], [3]]. By increasing training, imbedding laboratory expertise in crime scene responders, and increasing early access to forensic scientist laboratory expertise; analyses can be streamlined for an immediate “first pass” on a small subset of select items to provide critical investigative direction very early in the investigative life cycle. Timely results will guide subsequent analyses in consultation with investigators, as well as negate future non-probative analyses. The product is a “layered” or “tiered” analysis, with highly probative analyses guiding or eliminating less probative analyses, with the overall process taking fewer resources to deliver more valuable leads on fewer items with a quicker response. This layered analysis model also applies to screening conducted outside of the forensic laboratory, where information gained from screening tests guides confirmation tests at the laboratory.
The key feature of the concept of the Proactive Crime Scene Response is the active rather than a passive role played by forensic scientist experts in the investigation of crime. As major resources are being spent by investigators, timely forensic intelligence will make their decisions regarding the direction of the investigation much more targeted. Investigations will be driven by data rather than primarily eye witness’ accounts. As suspects are included or excluded, there is a cyclical back and forth reflux communication between investigators and forensic scientist experts to ensure all forensic evidence is followed up on and additional analyses done as needed. With maximum evidentiary value and data pulled from forensic evidence as quickly as it can be developed, investigators are acting on actionable data driven evidence regarding suspect identities and other concrete features, rather than relying exclusively on witness statements and other more subjective information. Forensic data can refute or support witness and suspect statements, providing investigators strong tools for interviews, statement preparation, and evaluation.
Timeliness is critical to maximizing the value of evidence. For example, knowing that a cartridge casing from a “shots fired” crime scene location is linked to a recent homicide is much more valuable a day after the shooting compared to a week, and much more so than a month later. Ironically, the same amount of work goes into each of these three examples, the only difference is the amount of wait time that the case experiences prior to analysis being started. The U.S. Bureau of Alcohol, Firearms and Tobacco (ATF) Minimum Required Operating Standards Audit for National Integrated Ballistic Information Network Sites (MROS) recognizes the time value of evidence, including a requirement for a 24-to-48h turn-around time for NIBIN acquisitions of crime scene casings [6]. While ideal if every case was started the day it arrived in the forensic laboratory, starting analysis on critical evidentiary items is capable of delivering an interim solution.
In this approach, the forensic laboratory analytical flow is prepared to accept probative items into the analysis queue immediately upon submission into the next batch being analyzed. Using a train metaphor, a newly submitted case would catch the very next train leaving the station. Pulling back a train that has left the station to insert new passengers (cases) is extremely detrimental to the overall train schedule and operation. There is indeed short-term benefit to a few passengers, but their insertion into the system creates chaos and inefficiency overall. The Proactive Crime Scene Response is akin to running express trains outside of the normal system or selecting party representatives of a group to ride the regular train. Less riders on a schedule in first class equals greater efficiency and less disruption to the entire body of the ridership.
Another component of the Proactive Crime Scene Response is to support the 2-step screening and confirmation process outside of the forensic laboratory. Screening conducted using NIBIN and Rapid DNA provides an accelerated response, however, requires support from forensic scientist experts for education as well as confirmation analyses.
The proposed method has been broken down into a description of the process steps, which include training, communication, structure, evidence collection and submission, analytical response, reporting, and reflux (review, discussion and additional submission where needed) as follows:
4.1. Training
Education on current and new forensic technology, best practices, refreshers, and updates is an ongoing mandate for crime scene investigators. Training must be formalized and documented for new crime scene investigators, as well as for periodic updates for existing personnel. Training can be provided in person, on-line via modules available on demand, through handbooks and cheat sheets, short instructional videos, hotlines to call and through contact with dedicated case liaison forensic scientist experts. Informal training occurs through the ongoing contact and support from career forensic scientist experts and liaisons abreast with new technology. Awareness permits recognition of high value evidence items, which can be collected, preserved, and expedited.
Mirroring accreditation requirements, crime scene investigators should undergo a competency test after training prior to commencing casework and be subject to regular proficiency tests to demonstrate capability. Training in the specifics of the Proactive Crime Scene Response and tiered analysis will ensure support and best use of the system, as well as enhance communication between crime scene and forensic scientist experts.
4.2. Communication
Forensic scientist experts provide training and are accessible for real time advice, as well as crime scene attendance. Notification of occurrence of crime with forensic laboratory involvement both to crime scene and to forensic laboratory personnel permits individuals with appropriate experience to be assigned. In this manner, the expertise can be tailored to the requirements of the crime scene and item types. Acquiring the best evidence and forensic intelligence requires actively reaching out to forensic scientist experts to ensure that valuable evidence is recognized, collected, preserved, and submitted to the forensic laboratory in a timely fashion. On call accessibility provides real time communication to criminal investigators. As time is money and money is spent disproportionately in the early investigative phases, information is conveyed directly to the investigation as soon as it is developed and reviewed. Continuous access to forensic expertise ensures the value of evidence is understood and acted upon. Investigators continue communication regarding the direction of investigation with forensic laboratory personnel, which in turn may drive additional rounds of forensic analysis (see point 4.8 Reflux).
4.3. Structure
Over time, many historically sworn forensic positions have transitioned to non-sworn scientist positions, notably in Firearms Sections, but progressively in Latent Print and Crime Scene Investigator positions. A challenge noted previously in staffing such positions as sworn personnel can potentially limit mobility and promotion, whereas many non-sworn personnel frequently stay in the field and discipline for an entire career. Changing positions from sworn to non-sworn personnel can be a long-term challenge and subject to many factors, including union and personnel regulations, tradition and changing mind-sets regarding what background is best to fill a particular set of knowledge, skills, and abilities.
In the shorter term, there are a number of strategies that can be employed to increase communication and access to expertise. These include but are not limited to the following variety of strategies on the communication and contact service delivery options menu: case agent liaison, imbedded rotating forensic scientist experts, on call forensic scientist experts or hotline, updated evidence “cheat sheets”, on-line training with short videos, video conferencing and training. Coupling a forensic scientist expert with a sworn investigator ensures best evidence collected and best intelligence provided to support the investigation.
Assigning an individual or a team of laboratory trained individuals to work directly with investigators builds relationships and breaks down communication barriers. This assignment can be permanent or in rotation, including having personnel on call to provide information at the time it is needed. Forensic scientist experts who are available to attend particularly problematic scenes to dispense advice are especially valuable (see Table 1: Forensic scientist experts). The time spent at the crime scene pays large dividends in selecting probative items at the crime scene, as well as determining those of limited or no forensic value. Items can also be prioritized, which facilitate the quick analysis of a subset of crime scene items.
Table 1.
Forensic scientist experts.
| Forensic scientist expert definition within the proposed system |
|---|
| Stable/dedicated (no turn-over, long term positions) career scientists with multidisciplinary forensic capability, heading a forensic team with liaison/direct assignment to criminal cases and their investigators. |
| Liaison to crime scene personnel to direct correct collection of evidence. Awareness of evidence types at crime scenes to be collected, to coordinate immediate assignment and commencement of forensic analysis. |
4.4. Evidence collection
Optimal recognition, documentation, collection, and preservation is based on the training discussed above, and following well-documented controlled procedures [[7], [8], [9], [10], [11], [12], [13], [14], [15], [16]]. The scene and items are documented and photographed. Appropriate personal protective equipment protects personnel, the environment and integrity of evidence, as contamination is mitigated/minimized. Proper packaging of items prevents deterioration of evidence as well as cross contamination, as items are packaged individually in breathable containers to prevent condensation and deterioration due to retained moisture. Fragile items must have customized packaging to prevent breakage. Wet items are to be air dried prior to long term packaging and storage. Contact with forensic expertise is available in real time for any questions and guidance. Work is reviewed and timely feedback is provided for continuous improvement. Crime scene work is commonly conducted in teams, as more than one perspective is very helpful to ensure all probative evidence is properly collected.
4.5. Submission
Timely evidence submission is facilitated by electronic submission systems. Duplication is avoided, as well as typographical errors reduced in case and item numbers, and other easily replicated and transferred data. Laboratory Information Management Systems (LIMS) can provide potential preapproval and facilitate immediate assignment of forensic specialists who can commence analysis upon submission to the laboratory. Submission of a limited number of probative items reduces the time spent in submission and evidence receiving, as well as documentation and storage overhead. Additional submissions are made as necessary, guided with intelligence provided by analytical results (see 4.8 Reflux).
4.6. Analytical response
Forensic analytical capability is required to begin cases as soon as evidence is collected and submitted to the forensic laboratory for analysis [1]. Coordination is required for evidence transport, receiving, storage and assignment. In complex cases there is a requirement for identification of multidisciplinary items (e.g. A fingerprint in blood on a gun). Multiple forensic sections must work together to conduct non-destructive analyses first, potentially dividing evidentiary material, sampling, repackaging, or conducting multiple examinations simultaneously. While rules can be set up for commonly occurring item types, such as sexual assault kits, the variety and complexity of items and evidence that may occur necessitates a consultative and collaborative approach to maximize evidentiary value.
A layered or tiered approach to forensic analysis is recommended. Using this approach, a first pass selects those particularly valuable items for expedited forensic lab analysis. Initial analysis is limited to only those items with very likely probative forensic evidence, particularly those items that will more likely provide an investigative lead, to direct the investigation. It is critical that analysis is started as soon as items enter the lab, to maximize the investigative potential and resulting savings from the forensic intelligence that is developed. Results from those items will negate or direct subsequent analyses depending on their value to the investigation. Subsequent to analysis of critical probative items of high forensic significance, additional items are considered in consultation between investigators and forensic scientist experts (see 4.8 Reflux).
4.7. Reporting
Timeliness is critical to the success of the Proactive Crime Scene Response. Each day that can be shaved from the response time is one less day a potentially dangerous suspect is at large, or a wrongful suspect bears inappropriate suspicion. Electronic reporting of analytical results provides a faster response as case analysis is completed. It also enables an audit trail for results dissemination as well as broad access by a variety of authorized stakeholders. This provides not only timeliness, but transparency and transferability of information between crime scene attending first responders, submitting agents, investigators, detectives, supervisors, and justice system officials. An audit trail feature serves as a check on privacy. An automated notification alerts submitting agencies that an analytical report is available the moment it is completed.
Interpretation of forensic findings contained in a report adds further value and is a major facet of communication. Meaning of the forensic analysis in context with the crime is provided, highlighting actionable investigative items, driving next steps in the investigation. Additional analyses and submissions can be discussed, approved, and expedited, as well as negated if analytical findings are particularly conclusive.
4.8. Reflux: review, discussion, and additional submission
Forensic expertise is constantly available to follow up on reporting to ensure interpretive meaning is correctly received and interpreted. Close professional relationships, training, and communication includes discussion of any next steps as needed.
Forensic information is frequently siloed along case submission guidelines, with other investigative agencies not aware of findings, as confidentiality limits data sharing. Frequently, forensic laboratories are aggregators of data from a large number of jurisdictions and crimes, providing an opportunity for an expanded multijurisdictional use of combined data [17]. Communication among police agencies to link crimes is important to solving those crimes committed by the same individual. Aggregated forensic intelligence can be mapped to locations and highlight trends, realizing value beyond that in the instant case. A dashboard can facilitate data viewing in real time, as analytical results are completed.
Once the first pass of forensic analysis is completed, the information gathered drives the second wave of analysis, if a second pass is required at all. Time saved in elimination of second pass analysis is used to drive quicker first pass analyses for the next cases in the queue.
Case follow up can occur on a regular schedule or on a case-by-case basis. As many cases may remain unsolved, a check can be provided regarding the status of cases at predetermined intervals. With development of new leads, new trends, new links to other crimes, and collective intelligence, a determination on what additional analysis may be needed to follow through and build upon work previously completed. Case and evidentiary item lists are generated for consideration for new emerging technology, such as forensic investigative genetic genealogy. In this manner, no cases are left behind, nor permitted to be forgotten and grow cold.
5. Case examples
Case examples which follow serve as practical illustrations of the Proactive Crime Scene Response. They demonstrate the key elements of the proposed approach: training, communication, expedited analysis of a subset of forensically significant key items, analysis, reporting, and follow up for additional analysis as required.
5.1. Clinton correctional facility escape
A quick turn-around time on probative analytical results saves investigative time and increases public safety. On June 6, 2015, convicted killers Richard Matt and David Sweat escaped from the Clinton Correctional Institute in Dannemora, NY (see Fig. 1) [18]. Approximately 1,000 officers and support staff were employed in the search, costing an estimated $1 Million per day of the search. Recognizing the need for a quick response, laboratory staff volunteers were canvassed to work around the clock and over weekends to deliver an expedited analysis on critical items. Within 12 h of submission to the forensic laboratory, DNA profiles were developed from items found at a cabin in Northeastern New York that was broken into. Findings confirmed the suspects were in a different part of the state than where resources had been previously assigned. An eyewitness tip had indicated that two men fitting the description of the escapees were walking along a railway track in Southern New York State, far from their actual whereabouts.
Fig. 1.
Convicted killers Richard Matt and David Sweat, escapees from the Clinton Correctional Institute in Dannemora, NY.
Sampled items from inside the cabin and nearby area included bottles and salt and pepper shakers, which were swabbed and analyzed for trace DNA. DNA profiles matching the escapees enabled reassignment of resources to the correct area, where law enforcement personnel were able to locate the suspects. One of the escapees, Richard Matt, was killed while he brandished a gun stolen from a cabin. The second escapee, David Sweat, was apprehended approximately 2 miles from the Canadian border. He was shot when he did not yield to law enforcement instructions to halt. Sweat survived his wounds with medical treatment to resume his incarceration.
5.2. Homicide of a twelve-year-old girl by a family acquaintance
Complex cases frequently involve multiple types of evidence, each of which can add value to an investigation. When taken together, their added weight can make the difference in solving a case through developing and eliminating suspects and corroborating or refuting alibis. In this second case example, forensic analysis included trace DNA, footwear impression examination and digital analysis of cellular phone information.
Jessica Nguyen, a twelve-year-old girl, was found brutally murdered in her basement bedroom. No evidence of forcible entry was found. The victim had been stabbed over 40 times suspected to have been with a small sword-like weapon. Leading away from the body and pooled blood was several bloody footprints. While the murder weapon itself was not found, DNA matching the suspect was found on a ceremonial knife sheath found near Jessica Nguyen's body. A bloody boot print matched class characteristics of boots that were assigned to area bus drivers, a population which included the suspect. The suspect had been assigned boots of the same make and model which produced the boot print. Cell phone records and triangulation provided a location demonstrating that the suspect was within a block of the crime scene at the time of the murder. This information refuted the suspect's version of events. He had provided a signed statement that he was nowhere near the homicide scene when it took place. The combination of this evidence along with other case facts providing motive were sufficient for a guilty verdict to the charge of murder [19].
5.3. A homicide disguised as a suicide
A third case example illustrates the capability of forensic education, close contact, and communication with forensic scientist experts in enabling investigators to recognize, collect and preserve crime scene items which can be successfully analyzed. Trace DNA is a particularly perishable type of evidence, which can be easily overlooked or contaminated when incorrectly handled. Recognition of the potential value of evidence lead to its proper collection and recovery, established with outreach to the forensic laboratory. Evidence processing was prioritized and involved an interdisciplinary approach which included firearms, latent prints, and DNA forensic expertise.
A 911 emergency call to attend a fatality was originally placed by a husband, reporting his deceased wife was in bed as a result of an apparent suicide. Reportedly, a single shot 12-gauge shotgun was originally purchased new as a birthday present for the couple's son. The shotgun allegedly arrived at the family home in an intact box and awaited the boy's birthday to be opened [20]. The crime scene investigator attending the scene documented the deceased in bed with her left hand grasping the middle of the barrel of the shotgun. Her right hand was laying on top of her chest in general proximity to the shotgun trigger area, however the trigger faced away from her body. A single fatal shot had been rendered below the deceased's lower jaw and the shotgun muzzle was located several inches above and to the left of the entry wound.
Several pieces of information surrounding the crime scene raised questions in the investigator's mind. The position of the gun and distance between the muzzle and the lower chin appeared that it would be difficult for the deceased to have pulledthe trigger. Further, the bed sheets and comforter were between the deceased and the firearm, with the shotgun laying above the bedding.
In consultation with Acadiana Criminalistics Laboratory staff, the shotgun was submitted for analysis. No latent fingerprints were found on the gun using cyanoacrylate fuming. The forearm, butt stock and hammer of the gun were then swabbed for trace DNA. The firearm itself was analyzed for operability, and it was determined a single shot was fired from the gun with the expended cartridge remaining in the firearm, and the hammer was required to be manually cocked each time for the firearm to discharge.
Analysis of the swabs taken from the shotgun are found in Fig. 2, Fig. 3, Fig. 4 for the forearm, butt stock grip, and hammer respectively. The DNA profile found on the forearm of the shotgun (Fig. 2) was a single source female profile which matched the deceased.
Fig. 2.
Profiler Plus DNA profile for shotgun forearm (images 2–5 courtesy of Acadiana Criminalistics Laboratory, Kevin Ardoin Director).
Fig. 3.
Profiler Plus DNA profile for shotgun butt stock grip.
Fig. 4.
Profiler Plus DNA profile for shotgun hammer.
A two-person mixed DNA profile was found on the shotgun butt stock grip (Fig. 3), which included the wife and her husband as potential contributors.
The DNA profile from the hammer was a single source male profile (Fig. 4), which matched the husband.
The box which contained the shotgun was found as seen in Fig. 5 in a clothes closet where it had been placed in preparation for the son's birthday.
Fig. 5.
Crime scene photograph of gun box in closet behind hung clothing.
In the husband's sworn statement, he indicated the shotgun was purchased new, arrived in the box, and he had never handled it. Therefore, the finding of the husband's DNA on the gun, particularly the hammer was pivotal. The gun could only be fired after the hammer was manually cocked, and there was no trace of the wife's DNA on the hammer; only a single source DNA profile matching the husband.
Further investigation indicated that two weeks prior to the incident, the husband had contacted their insurance company to confirm that he was the beneficiary of his wife's $250,000 life insurance policy and that it paid in the event of a suicide [20]. Additional case investigation details include that when emergency workers originally showed up, the husband was sitting in front of the home drinking wine. He confided to a woman he asked for a date a week after the incident that while his wife lay dead, he put in a load of laundry and sat down to watch television before making the call, according to the woman's testimony. She also related that he talked of moving to an island after he got the insurance money [20].
The husband was found guilty of second-degree murder for the shooting death of his wife, and resulted in a mandatory life sentence.
5.4. Analytical results clarify conflicting statements in a homicide investigation
To illustrate the potential of the Proactive Crime Scene Response to clarify conflicting witness statements in a crime investigation, consider this case from the author's personal experience:
The case was a homicide where 14-year-old Darelle Exner was found murdered and dumped in a window well in Regina, Saskatchewan, Canada. As her clothing was removed, there was suspicion of a sexual assault. The victim had visited a local hamburger restaurant with her friend and boyfriend [21]. She was in the ninth grade at a local Catholic high school. Her curfew was 9:00 p.m., which was earlier than her friends. Rather than break her curfew, she chose to walk 4 blocks to her house alone. As the time of year was late fall, it was after dark. Darelle did not make it home and was found by a young man and his girlfriend the next day after being reported missing by her mother when she missed curfew the previous evening. The young man who discovered the body included in his statement that when he was out walking the previous evening, he had come across three men who appeared suspicious and, in his words, “were up to something”.
Shortly following the discovery of the body, the local City Police Department brought evidence items for submission to their local forensic laboratory, however forgot some key pieces and had to go back to the station. The forensic scientist expert received evidence directly from contributors in their local forensic laboratory with no separate evidence receiving section, therefore the scientist was left to await the investigators return, whose round trip was approximately 30 min. Items of evidence that were submitted directly to the analyst were items of clothing assumed to be from the deceased (which were a short distance from her body), a sexual assault kit including vaginal swabs, and known DNA samples from her, her boyfriend, and the individual who found the body.
Given the scientist had approximately 30 min to wait, the scientist took the evidence up to the wet laboratory area, secured the evidence that had been obtained, and examined the vaginal swab for the presence of semen. The acid phosphatase presumptive test for seminal fluid rapidly turned purple, indicating a positive result. A slide was made from the swab and a quick visual microscopic examination demonstrated that sperm was very abundant, and virtually all sperm had intact tails. Due to the large number of sperm, the scientist related to the investigators upon their return with the remaining evidence that there would very likely be a forensic DNA profile that could be deduced to a male single source once the DNA analysis was conducted. The scientist immediately began the DNA process for the vaginal swab and the two suspect swabs (boyfriend and individual discovering the body). The scientist also advised investigators that they should not expect this level of service on every case. In hindsight, to this day that remark still sticks in the author's brain. Why not?
In the ensuing investigation which quickly became very high profile due to the nature of the missing girl and the discovery of her body, the City Police had located and questioned the three young male suspects. These three suspects were the same individuals who had been out the previous evening and were referred to in the statement of the young male who found the body. Police investigators charged the three with the homicide. Each had denied participating in the homicide but implicated their two companions. The murder charges were reported widely by media. Unable to obtain a direct confession from any of the three suspects, based on their combined statements, they were being held for further questioning. Three known samples, one from each of the suspects were obtained and submitted to the scientist for expedited DNA analysis (Items 5–7 inclusive, see Table 2). Given that DNA analysis had already commenced on the four previous samples (vaginal swab and known samples from the deceased, the boyfriend and the individual who found the body), the three new additional suspect known samples were run in a second batch of DNA samples. Standard procedure for the laboratory dictated that known samples were processed separately from questioned crime scene samples.
Table 2.
Catalog of evidence submitted for forensic analysis.
| Item 1: vaginal swab (deceased sexual assault kit) |
| Item 2: known sample – deceased 14-year-old female |
| Item 3: known sample – boyfriend (Suspect 1) |
| Item 4: known sample – individual finding the deceased (Suspect 2) |
| Item 5: known sample – suspect 1 of 3 individuals out the night of the crime (Suspect 3) |
| Item 6: known sample – suspect 2 of 3 individuals out the night of the crime (Suspect 4) |
| Item 7: known sample – suspect 3 of 3 individuals out the night of the crime (Suspect 5) |
As a result of laboratory procedures, separate batches of DNA results were obtained for the vaginal swab (Item 1) and known samples. Known samples included the deceased (Item 2), the boyfriend (Item 3), the individual finding the body (Item 4) and the three suspects (Items 5–7 inclusive). A mixed DNA profile was obtained from the vaginal swab (Item 1) and as expected, due to the large amount of male contribution present, a straightforward accounting for the female profile revealed a deduced single source male DNA profile. This forensic profile was compared to the five known profiles (Items 3-7, see Table 2) that had been submitted. A match was made to the individual who had found the body, Suspect 2 (Item 4). The other suspects, Suspects 1, 3, 4 and 5 (Items 3, 5, 6 and 7) were eliminated as potential contributors of the male DNA profile obtained from the sperm found on the vaginal swab from the deceased, Item 1. Once the result was technically reviewed by a second qualified scientist, the result was relayed to investigators via telephone. Shortly thereafter, the City Police requested and obtained an in-person meeting with the scientist.
The scientist attended the meeting at the City Police Headquarters, which included the detectives and City Police major case management. Each step of the case including the flow of analysis was reviewed, to ensure the results were accurate prior to action being taken on the case. Based on that discussion, as well as review of the laboratory process to ensure integrity of samples, the individual finding the body (Suspect 2) was sought for questioning. When the individual was not located, a nationwide warrant for his arrest was issued. In that manhunt, Suspect 2 was located over 2500 km away and brought back for questioning. When faced with the DNA evidence, Suspect 2 admitted to the crime. Apparently, he had an argument with his girlfriend the previous evening, and he left angry. Suspect 2 then came across the victim and committed the crime. Some time while out walking that same evening, he had seen the three previous suspects on the street (Suspects 3, 4 and 5). Concurrently, investigation on Suspects 3, 4 and 5 had not revealed any association with the victim, no witnesses, nor evidence that could connect the three to the crime scene, besides their conflicting statements. Charges were therefore dropped against Suspects 3, 4 and 5 and charges were placed on Suspect 2. While the media reported the dropping of charges on Suspects 3, 4 and 5 and homicide charges on Suspect 2, there was a cloud of confusion upon what new information had resulted the change of direction. Justice system officials decided they did not want to try the case in public and jeopardize objectivity, and thereby determined that no additional information would be provided to the media.
As the trial approached, the media and public were keen to understand the events of the case. One of the lead suspects among the group of three eliminated by the DNA evidence (Suspect 3) was scheduled to testify at the trial. This testimony was intended to set the record straight regarding the rationale for the conflicting statements, to put potential jury and public concerns to rest regarding events of the crime and its investigation. The day prior to the lead eliminated suspect's testimony, Suspect 3 could not be located. Subsequently, the trial was halted, and a nationwide warrant was issued for the fleeing witness. Media interest in the sequence of events was intense.
One of the original crime scene investigators (coincidentally a neighbor of the forensic scientist expert) was competing in a marathon at an international Police-Fire Games approximately 800 km away. As the marathoning investigator neared the finish line with the banner in sight, in the front of the crowd of cheering spectators was the fleeing witness. Stopping the marathon just short of the finish line, the crime scene investigator arrested the witness, Suspect 3. The following week after news of the arrest event circulated widely, the trial resumed with the highly anticipated testimony of the eliminated witness after his transport and return. According to Suspect 3's testimony, he and his two companions (Suspects 4 and 5) felt pressure under questioning and felt compelled to say whatever was required in an attempt to remove doubt from their own culpability to the point that they falsely incriminated their companions. When questioned upon the reason for his flight from the trial, Suspect 3 admitted to panicking and questionable decision making. The weight of the DNA evidence and the confession of Suspect 2, along with the explanation given by the returning witness Suspect 3 resulted in Suspect 2 being found guilty of the homicide.
Timely forensic evidence eliminates and implicates. Objective data-based evidence is very effective in driving investigations with facts, while statements from suspects can be prone to inaccuracy as demonstrated in this case. While an extremely quick forensic result was available to guide the homicide investigation in this case, the analytical response was not the norm at the time, nor is it perhaps typical today. Thus, the argument for the Proactive Crime Scene Response is supported to seize the opportunity to assist investigations and justice as quickly as forensic technology can provide. That ideal response is starting case analysis as soon as a case can be submitted, as occurred in this case.
5.5. Trace DNA on knife handles
Another final forensic case illustration is provided where trace DNA eliminated an original suspect and implicated another individual. In a small town in Saskatchewan, Canada, an individual broke into a residential home where twin daughters slept in bunk beds. Removing two steak knives from the kitchen drawer, he used one of the knives to fatally stab the twin daughter sleeping in the lower bunk bed. Both daughters awoke and immediately began screaming. Their father ran to their aid, colliding with the suspect in the dark hallway prior to the light being turned on. Unaware of the seriousness of the crime at that moment, the father struggled with and threw the suspect from the residence.
After police and emergency officials attended the scene to investigate, the father was questioned. As the home was dark when the father encountered the suspect, he incorrectly identified the individual as a local young man. Police interviewed the male suspect implicated by the deceased girl's father, and discovered the male suspect was employed at an all-night gas station. Video tape documented that the male suspect was continuously at the gas station serving customers throughout the time when the crime was committed. As suspicion fell upon the father, the father obtained a lawyer, and communication with investigating officers became limited and strained.
The entirety of the case items was submitted to the forensic laboratory. The scientist had kept informed regarding latest technological developments at the time including the potential to obtain DNA from handled objects, and therefore swabbed the handles of the two knives, and obtained trace DNA profiles. Foreign male DNA profiles were obtained which eliminated the father and implicated an unknown male [22]. Several weeks later, an unprovoked attack in a nearby town where the victim resisted her attacker resulted in a DNA profile obtained from the victim's collar and shoulder area, where the attacker cut himself and deposited blood. The male profile from the previously unconnected assault matched the DNA profile from the homicide of the twin girl [22]. The attacker was subsequently found guilty of the homicide.
6. Results
Examination of these case studies highlight attributes of the Proactive Crime Scene Response and demonstrates the potential of selecting a subset of forensically valuable items for expedited forensic analysis. This approach is critically supported by crime scene investigator education and communication with forensic scientist experts. This improved education and communication permit the use of multiple forensic disciplines simultaneously to provide complementary evidence to solve crimes. The Jessica Nguyen 12-year-old homicide (Case 2) demonstrates the value of an interdisciplinary approach including a cellphone location to link a suspect to a crime scene, which corroborates or refutes the suspect's alibi. While the shoe print did not have a direct match to footwear owned by the suspect, the print was linked by class characteristics to footwear assigned him by his employer, which provided a more general association. Taken together with other facts in the case, a composite picture can be provided to the finder of fact to assist in their determination of guilt or innocence.
Expedited analysis of selected items provides an illustration of the cost saving potential of actionable objective evidence. The New York Clinton prison break (Case 1) not only subjected the public to a safety risk, but the statewide search also involved over 1,000 law enforcement personnel. Beyond the cost of these personnel and their resources, their regular duties were supplanted to enable the search for the escapees. Real time forensic analysis saved resources by directing the investigation with concrete information, which resulted in apprehension of the escapees within days of the analytical results. More rapid resolution enhances public safety by limiting exposure of the public to victimization by recidivist offenders.
The homicide disguised as a suicide case (Case 3) highlights the value of education, evidence recognition, and communication with the forensic laboratory regarding case specifics. Training regarding trace DNA enabled the investigator to recognize the investigative potential of the shotgun. Use of the disciplines of firearms and DNA, detailed crime scene documentation, coupled with investigative interview statements coalesced to refute the suspect statements and provide a direct association to the shotgun. Additional investigation revealed additional witnesses and statements that provided the insurance money motive for the homicide, as well as refuting potential alibis to explain the presence of DNA on the shotgun.
The timely result used to eliminate the 3 charged individuals and implicate the subject “finding” the deceased (Case 4) illustrates the critical nature of a rapid analytical response driving complex investigations. Likewise, the case of the two knives (Case 5) demonstrates the importance of forensic evidence to clarify the father's statement. The videotape alibi for the male suspect implicated by the father highlights the variety of media available to drive investigations with facts, conclusively eliminating suspects. The cross comparison of cases (and databases) provided by DNA to develop suspects, make DNA and forensic evidence pivotal tools for investigators.
Knowledge of new technological potential was critical to providing an investigative lead in the case of the two knives. In both Cases 4 and 5, statements taken from individuals under suspicion of committing crimes are demonstrated to have varying accuracy. At times the inaccuracy is due to involvement in a crime (Case 4, Suspect 2), fear of implication, misunderstanding and succumbing to fear which drives questionable decisions (Case 4, Suspects 3, 4 and 5) or poor conditions including darkness, stressful situation, and honest mistakes (Case 5, father of the deceased twin). In each of these cases, fact based forensic results are a godsend to direct investigations potentially mired with incorrect and conflicting statements. In the absence of such conclusive forensic results, cases can lead to wrongful suspicion or worse, wrongful conviction. Hence, timely forensic results are critical for protection from wrongful suspicion and conviction, as well as public safety resulting from pursuing the correct suspect.
Key results of the examination of the 5 case examples support the following attributes of the Proactive Crime Scene Response are found in Table 3.
Table 3.
Key aspects of the Proactive Crime Scene Response.
| Proactive Crime Scene Response – Key Aspects |
|---|
|
|
|
|
|
|
See Table 4 for examples of high value forensic targets for associative evidence.
Table 4.
High value forensic target examples.
| Item | Evidence Type | Value |
|---|---|---|
| Blood sample | Blood alcohol and toxicology | Potential identification and level of alcohol and drugs |
| Crime scene | Blood, especially trail leading away from scene | Potential DNA evidence linking suspect to scene |
| Broken vehicle parts | Potential vehicle make and model, physical comparisons to suspect damaged vehicle | |
| Discarded partially consumed food items, cigarette butts, bottles, etc. | Potential DNA and latent print evidence linking suspect to scene | |
| Expended cartridge cases | Potential caliber, make and model, comparisons to other expended cartridge cases and suspect guns, entry into NIBIN to develop investigative leads; potential touch DNA analysis and comparison of forensic profile to suspect known or DNA databank todevelop investigative lead | |
| Latent prints, especially in blood | Potential comparison to suspects and latent print database to develop investigative leads; combined with DNA analysis of blood compared to victim and suspect | |
| Projectiles | Potential caliber, make and model, comparisons to other projectiles and suspect guns | |
| Shoe print | Potential make and model, physical comparison to suspect shoes | |
| Tire track | Potential make and model of tire and vehicle, comparison to other tire tracks and suspect tires | |
| Weapon | Potential associative evidence linking suspect and victim to weapon and scene, including latent prints, DNA, textile fibers; textile damage assessment (see Weapon below) | |
| Crime Scene - Point of entry | Latent prints | Potential comparison to suspects and latent print database to develop investigative leads |
| Toolmarks | Potential comparison to other toolmarks and suspect tool | |
| Deceased | Fingernail scrapings | Potential identification of body fluid type, DNA analysis and comparison of forensic profile to suspect known or DNA databank to develop investigative lead |
| Known samples (blood, hair, etc.) | Potential comparison to evidence at scene, on weapon and/or suspect; elimination sample including for DNA mixture deconvolution to increase probative value | |
| Semen, blood or saliva (foreign) | Potential identification of body fluid type, DNA analysis and comparison of forensic profile to suspect known or DNA databank to develop investigative lead | |
| Expended cartridge case | Firearms examination including NIBIN | Potential caliber, make and model, comparisons to other expended cartridge cases and suspect guns, entry into NIBIN to develop investigative leads; touch DNA analysis and comparison of forensic profile to suspect known or DNA databank todevelop investigative lead |
| Firearm | Firearms examination including NIBIN | potential caliber, make and model, operability, test fires to generate projectiles and expended cartridge cases for comparisons to other expended cartridge cases, projectiles and suspect guns, entry into NIBIN to develop investigative leads; latent prints; touch DNA analysis and comparison of forensic profile to suspect known or DNA databank todevelop investigative lead |
| Known samples | Victim and suspect buccal swab | Comparison to evidence at scene and/or on suspect/victim and/or on weapon, elimination sample for DNA mixture deconvolution to increase probative value |
| Projectile | Firearms examination | Potential type, weight and caliber, comparisons to other projectiles and suspect guns |
| Saliva | Oral fluids toxicology | Potential evidence of drug use (e.g. THC) |
| Sexual assault kit | Swabs of personal areas and/or clothing for semen, blood and/or saliva | Examination for body fluids, identification, DNA analysis, comparison of forensic DNA profiles to suspect known or DNA databank to develop investigative leads |
| Solid substance powders or pills | Seized drugs | Potential controlled dangerous substances identification and quantitation |
| Suspect clothing | Blood | Potential identification of body fluid, DNA analysis and comparison to victim and/or suspect known or DNA databank to develop investigative leads |
| Urine sample | Toxicology | Potential controlled dangerous substances identification and quantitation |
| Vehicle | Blood | Potential identification of body fluid, DNA analysis and comparison to victim and/or suspect known or DNA databank to develop investigative lead |
| Broken or missing parts | Potential identification of make and model, physical comparisons to broken parts from scene | |
| Fabric Impression | Potential identification as a fabric impression and comparison to a questioned fabric | |
| Hair | Potential identification as human hair with descriptors (length, color, treatment, damage, etc.), DNA analysis and comparison to victim and/or suspect known or DNA databank to develop investigative leads | |
| Saliva | Potential identification of body fluid, DNA analysis and comparison to victim and/or suspect known or DNA databank to develop investigative leads | |
| Touch DNA on steering wheel | Potential DNA analysis and comparison to suspect known or DNA databank to develop investigative lead. Note that a known sample from the car's normal legal driver is required for elimination. | |
| Weapon – club, knife, etc. | Blood | Potential identification of body fluid, DNA analysis and comparison to victim and/or suspect known or DNA databank to develop investigative leads |
| Latent prints | Potential development and comparison to known samples from suspects and latent print database to develop investigative leads | |
| Touch DNA | DNA analysis and potential comparison to victim and/or suspect known or DNA databank to develop investigative leads | |
| Weapon - firearm | As per weapon above, however, add Firearms examination | Potentially identify caliber, make and model, comparisons to expended cartridge cases and projectiles, operability and test fire, entry into NIBIN to develop investigative leads; latent prints; touch DNA analysis and comparison of forensic profile to suspect known or DNA databank todevelop investigative lead |
Table 4 is not an exhaustive list of high value forensic target items, however, provides examples of the types of items commonly occurring at crime scenes and in crime investigations that are capable of providing valuable evidence and associations to direct investigations with timely analytical results. Crime scene investigators should consult their local forensic laboratory and forensic scientist experts to ascertain the types of analyses they are equipped to conduct.
7. Technology and analytical workflow
Application of a tiered or layered analysis means that evidence items are not all treated equally. Higher forensic value items are tested first, providing information to guide subsequent analyses, or inform that further analysis may be rendered redundant or not required. Analytical techniques themselves are also not created equally. More general, quicker but less specific or less conclusive analyses are frequently employed as screening tests, providing a fast response to guide subsequent analyses. These subsequent analyses include more specific confirmation tests, which typically take more time and apply more complex procedures and instrumentation but permit a more definitive conclusion. This same screening and confirmation 2-step strategy can also be employed outside of the walls of the forensic laboratory, where screening tests such as drug field test kits provide a quick response. Field test results are supported with confirmatory analyses by an accredited forensic laboratory which in turn issues a report and expert testimony as required.
Ideal application of screening tools, techniques and instruments include those that are non-destructive, quick and informative. Portable laser spectroscopy provides the capability to move the forensic laboratory to the crime scene, rather than taking samples directly to the laboratory [23]. The result are rapid non-destructive analyses that are performed in-situ, reducing sample handling, alteration and potential for contamination. It has a further advantage of not requiring reagents and consumables. Screening results may reveal aspects of biological stains that include information regarding its originators, such as sex, potential demographic information, time since deposition, type of body fluid, and other valuable information which can guide evidence evaluation, selection, collection, and down-stream analysis [23].
This screening and confirmation 2-step analytical approach can also be applied using Rapid DNA and NIBIN (National Integrated Ballistics Information Network). In each technology, a quicker response via a “screening” analysis is provided as an investigative lead, which enables investigations to move forward, while longer more detailed confirmation testing is conducted for judicial proceedings. Rapid DNA is capable of providing a DNA profile from single source samples in 90 min. A single source forensic profile can be compared against suspect known samples, or to a database to provide investigative leads. Similarly, NIBIN contains images of expended cartridge cases which are matched against forensic specimens to provide an investigative lead to permit investigators to move ahead with their cases. Confirmation of leads is performed in an accredited forensic laboratory by firearms experts conducting a direct comparison of the forensic expended cartridge case to the known exemplar using a comparison microscope. While this work is more painstaking and requires extensive firearms expertise and training, it is required for expert reporting and testimony. Hence the 2-step screening and confirmation approach for analyses enables a quick response backed by more specific confirmation.
A critical facet of the 2-step screening and confirmation approach is that the original sample is not consumed or significantly altered in the screening process. With techniques such as Rapid DNA which consume a sample, care must be taken to retain enough sample for analysis at an accredited forensic laboratory. For those samples of limited quantity, such as trace DNA evidence, the samples should be submitted directly to the forensic laboratory. Similarly, samples suspected to be from more than one donor should also be submitted directly to the forensic laboratory as Rapid DNA is not currently suitable for mixed DNA samples. Therefore, establishing procedures and training to obtain 2 samples from each probative item thought to be from a single source for Rapid DNA is critical for an effective program.
While improved public safety is compelling rational for a quicker response time enabled by a 2-step approach, a perhaps more compelling argument is the expedited elimination of innocent suspects. A quick analytical response provided by Rapid DNA, can swiftly eliminate a wrongful suspected individual with 100% certainty for a very probative sample. In the case of the two Marks an individual who appeared identical to the true perpetrator was eliminated by DNA while a DNA database hit linked to the appropriate individual [3]. Both individuals were coincidentally named Mark, which was the name the perpetrator provided to the victim, who in turn described and identified her assailant. Due to an incredible physical resemblance of two men, her identification was incorrect, which was borne out by the DNA analysis. Unfortunately, significant time elapsed where the incorrect individual was under suspicion while analysis was conducted with slower technology, with his rights potentially being compromised. Employment of quick screening technology such as Rapid DNA is a protector of individuals rights by quickly eliminating the wrongfully accused, as well as an enabler of improved public safety by holding a suspect accountable before more crimes can be committed.
The quick and portable DNA response enabled by Rapid DNA instruments also has a very large potential positive impact on disaster victim identification (DVI) scenarios. Family assistance centers are utilized to support victims’ families and include obtaining known DNA samples to assist in potential victim identifications. Psychological and emotional support is provided to family members through several avenues, including assembling a team of professionals at family assistance centers. As the forensic samples found at disaster sites are often single source, Rapid DNA provide forensic profiles that are compared to known samples from potentially biologically related individuals. Samples from personal items thought to be from potential victims can also be provided. The quick 90-min analysis time can be pivotal in providing feedback that known samples are not sufficient and must be retaken. If matches are made between biological relatives and a victim, this potentially very emotional information can be provided personally to family members while specialists are present to provide support and deliver information in the most appropriate manner and setting.
A model for disaster response readiness includes cooperation of agencies employing Rapid DNA instruments in different locations using the same procedures and infrastructure. When an event occurs, trained staff and instruments can be mobilized and deployed on site wherever the disaster takes place. Rapid DNA assistance can be provided from any one of a group of Rapid DNA providing “nodes” that are situated around a jurisdiction, state or country. Provided agencies are using the same system, instruments and procedures, teams can be scrambled to respond to any emerging situation to provide a coordinated DVI response. As with any system, Rapid DNA instruments should be in use on a regular basis to provide readiness for when a disaster may occur. Similar to a car that is only driven every 5 years, if counted upon when a trip is needed, an instrument may not perform as intended if left dormant. Should the car be driven daily, when needed on a trip, moving it to a new location for use becomes routine. Using this preparedness model, Rapid DNA instruments in routine use are in a state of constant readiness for deployment across a wide area to provide a timely national disaster response.
8. Business case summaries
While the argument for timely quality results on best forensic evidence is well supported logically, it is also strongly supported through a variety of business cases. Therefore, included in this summary discussion are a variety of cost benefit calculations from published articles. This very high value of applying technology to solve crime demonstrates the opportunity cost of appropriately balancing resources to ensure an expedited forensic crime scene and analytical response. Solving a crime where a suspect is not immediately available frequently requires the use of forensic science to assist in developing a suspect, facilitated through use of forensic databases. The cost benefit and returns on investment of a timely forensic response providing investigative leads are extremely large, showing several dimensions of investment. These dimensions include the elimination of backlogs and increasing the speed of response [1,24], performing analysis on all sexual assault cases [25], expanding the DNA database [3,24,26,27], performing Forensic Investigative Genetic Genealogy (FIGG) [28] and indirect matching [29].
Both increased use of forensics at the crime scene as well as populating databases of known samples for searching have shown very high returns on investment (see Table 5 for business case summaries) . A study of conducting forensic testing on all sexual assault kits demonstrated a return on investment of $98.74 to $645.29 per $1 spent [27]. The return on investment in a Louisiana cold case project demonstrated the analysis of all sexual assault cases returned $6546.63 per $1 spent [24]. Providing quicker analytical results likewise demonstrates very large savings, as improving response time by 1 day saves $1677.75 per $1 spent [3].
Table 5.
Return on investment from forensic DNA initiatives.
| Initiative | Return on Investment |
|---|---|
| Testing all sexual assault kits [27] | $98.74 to $645.29 per $1 spent |
| Louisiana sexual assault cold case project [24] | $6546.63 per $1 spent |
| Improving response time by 1 day [3] | $1677.75 per $1 spent |
| Increasing database size (for Louisiana cold case project) [29] | $53.52 per $1 spent |
| Social cost savings of increasing the database size [26] | $1566 to $19,945 per profile |
| Increasing database size universally (USA model) [29] | $4050.47 per $1 spent |
| Forensic Investigative Genetic Genealogy (FIGG) [28] | $311.19 per $1 spent |
Increasing the size of DNA databases of known offenders is also a sound investment in solving and preventing crime. Increasing DNA database size saves $53.52 per $1 spent based on a single cold case project in Louisiana [29]. The social cost savings of increasing the database size is between $1566 and $19,945 per profile [26]. Increasing DNA database size universally using a US model provides a $4050.47 return on investment for every $1 spent [29]. Furthermore, solving previously unsolved cases through innovative techniques such as FIGG has demonstrated a return on investment of $311.19 per $1 spent [28]. Thus, expanding use of forensic science at the crime scene, quicker response times, broader database use, and wider application of forensic technology are very valuable crime solving initiatives, evidenced by very large monetary savings in the cost of crime.
Applying screening tests outside of the forensic laboratory which enable a quicker investigative response such as Rapid DNA and NIBIN have the capability of providing substantial savings of the cost of crime. Note that improving the laboratory response time by one day saves $1677.75 per $1 spent [3]. While confirmation tests are still required for judicial proceedings, timely investigative leads enable investigations to move forward while more extensive analyses are conducted at the forensic laboratory. This layered or tiered 2-step approach enables investigators to stop a perpetrator much quicker, resulting in significant savings while more detailed analyses take place prior to court proceedings.
The very positive returns on investment demonstrate that timely use of forensic analysis should be performed on all cases where forensic evidence occurs. The Proactive Crime Scene Response enables implementation of expedited analysis on a targeted subset of forensic sample focusing on those most likely to provide a probative result. These results serve to guide additional analyses, however, is predicated by improved education, training and communication between crime scene investigators and forensic scientist experts.
9. Discussion
Forensic laboratories are an integral component of the criminal investigation and justice system, holding particular importance for crimes against the person where the use of databases can provide investigative leads in no-suspect cases. Objective evidence based on data directs investigators and the finder of fact. Better data guides better decisions. The crime scene is the origin of forensic evidence. Input of quality evidence is critical to the successful use of factual data to further justice. Evidence must be properly identified, documented, and protected against contamination, in order to be optimally collected, packaged and transported to a forensic laboratory for subsequent analyses. An overall goal for this process is evidence value maximization. An additional critical factor included in this maximization of evidence value is timeliness. Investigative and justice system resources are better applied the quicker results can identify items, as well as associate or eliminate suspects from further suspicion [30].
Crime scene analysis possesses several inherent limitations that hamper its effectiveness. At the time of the crime, frequently little is known of the potential suspects, or the paths the investigation may eventually lead as more information comes to light. As a result, a shotgun approach is frequently taken in gathering of evidence at a crime scene. All possible items of evidence are seized, in the event they may be needed. Frequently, there is only one opportunity to gather evidence due to its perishability. Perishability is a decline in quality and evidentiary value over time, as the crime scene can only be held for a finite time. Therefore, it is prudent to over-collect all potential evidence in conducting a thorough job of crime scene processing.
This prudent over-collection of evidence at crime scenes unfortunately may lead to difficulties in the investigation downstream, particularly with their forensic examination. Investigators and attorneys frequently misunderstand the concept that there is limited opportunity to collect evidence, and hence it is over-collected. All manner of evidence types is collected and often not needed depending on the twists and turns the investigation may take. However, just because an item of evidence is collected, does not mean its analysis will provide meaningful results. It is prudent practice to collect all evidence in the event it may be needed, with the understanding that much of it may remain unanalyzed, and this is to be expected. There is commonly a fear of criticism that items of evidence remain unanalyzed. This fear often arises from a lack of understanding of the dynamics of the crime scene relative to investigative information and forensic analysis. Decision makers must have confidence in conducting only those analyses which are meaningful, as investigative information which is gathered post evidence collection provides valuable analytical direction.
A negative byproduct of over examination of low value evidence is that it can lead to results that are not only non-probative but may associate individuals that have no connection to the crime itself. An example would be to analyze a cigarette butt a half a block away from a deceased victim in a downtown urban environment. As the cigarette butts in this case example are not very likely connected to the crime, any data derived is of limited or no value, and hence will dilute resources away from probative evidence, or otherwise could be better spent on the next case. False leads also provide the potential for not only wasted resources, but worse yet, wrongful suspicion or convictions. Therefore, examinations must be limited to those of probative value, which can be reasonably linked to the crime at hand.
Forensic laboratories with limited forensic resources face difficult choices regarding allocation of rare resources. In the worst-case scenarios, lack of resources may result in cannibalization of forensic disciplines and minor crime types. While it may appear prudent to focus limited resources on major crimes and forensic disciplines in what appears to be the highest value of evidence, it is notable that 86% of Florida DNA Databank hits occurred as a result of individuals placed in the DNA database for minor crimes [31]. Hence, solving minor crimes leads to solving and preventing major crimes. As minor crimes frequently lead to major crimes, the preventative aspect of expanded testing warrants its support.
One common counter argument to the use of targeted analysis of critical evidence is that knowledge of the particulars of a crime may bias the forensic scientist expert responsible for its forensic analysis. The extension of this argument is that the forensic scientist expert should not know about crime specifics but rather provide their analysis in a vacuum of information, thereby eliminating the potential for confirmation bias. A typical response begins with description that the standard of forensic practice dictates evidence is over-collected due to limited time for crime scene access and limited knowledge of the potential avenues for investigation at the time of crime scene processing. The next part of the response includes that prudent use of rare resources eliminates fruitless examination types, based on guidance from investigative information.
A useful analogy regarding the realities of practical resource constraints and the forensic crime scene approach can be illustrated using a visit to a doctor's office as a metaphor. A patient visits the doctor's office with an ailment. The doctor arrives, and her question to the patient is invariably a request to the patient, “What seems to be wrong?”
Without understanding of the forensic approach, a patient concerned about bias could respond, “You're the doctor, you tell me.”
Clearly, some knowledge of the nature of the crime and surrounding relevant information must be provided to forensic scientist experts, as resources do not exist to analyze every item from the crime scene including those of no forensic value. Information not pertinent to the selection of probative items should be shielded from those responsible for forensic analysis. Forensic analysis should be conducted with knowledge for the potential for bias [32]. Quality systems should include quality assurance features of competency testing, validation, proficiency testing, quality controls, ongoing training and other measures included in accreditation to guard against bias, as well as conducting thorough corrective actions and root cause analyses where quality issues do occur.
Overcollection of evidence and potential unnecessary analysis of non-probative items may have additional detrimental impacts. These include the space, storage and evidence handling considerations that accompany over-collection of crime scene evidentiary items. These issues are unfortunately a necessary byproduct of a thorough crime scene response, where new technology is constantly improving sensitivity and widening the spectrum of items which can be successfully analyzed. Any information that can be provided from both investigators and forensic intelligence can be vital in terms of limiting over-collection, retention, and forensic analysis. This is a careful balance and judgment as to what may be probative and what is not, as well as which items should be retained over the longer term. This balance is better informed by close monitoring of emerging forensic technology. Many forensic laboratories return all evidence, while others retain sampled portions of probative items. Given the increasing speed of forensic technological advancement, consideration should be given for coordinated, controlled, long term storage of key forensic items and samples.
Specialization of duties has further increased the need for communication on best practices for evidence value maximization. The ever-increasing level of technology has elevated the number of forensic subspecialities highlighting the need for ongoing education and training for crime scene investigators. Implementation of these best practices include adoption and adherence to OSAC (Organization of Scientific Area Committees for Forensic Science) forensic registry standards [33]. With often only one opportunity to process a crime scene correctly, having up to date information, crime scene support and use of best practices are critical. The wide variety of crime scene complexities further presses the need for real time consultancy on a case-by-case basis where necessary, to support the maximization of evidentiary value. Increases in the demand for forensic analysis and specialization of forensic disciplines challenges informal processes and relationships, particularly as staff turnover occurs. Therefore, creating a crime scene support system that builds upon personal relationships with an organized structure ensures continuity and consistency, particularly for challenging forensic cases.
The optimal value of forensic evidence is that which is analyzed and provided as quickly as possible [1], commencing analysis the day it is submitted to the forensic laboratory. Starting cases upon laboratory arrival facilitates a Proactive Crime Scene Response. In ideal circumstances, analysis of all forensic cases would commence as soon as a case was received at the forensic laboratory. The realities of restricted resources make shifting some component of resources to address a subset of critical cases a viable option. It has been said “if you cannot get the chicken, get the egg”. Portable instrumentation, NIBIN and Rapid DNA provide probative screening results to enable investigations to move forward while forensic analyses are completed for confirmation. The resulting rapid screening backed with expert confirmation provides public safety while quickly eliminating the wrongfully suspected.
An investment in forensic science is an investment in public safety and protecting individual rights. Quicker solving of crimes reduces individuals’ ability to commit additional crimes, thereby enhancing public safety. Associating an individual also goes hand in hand with eliminating other suspects, thereby improving their privacy by focusing investigations away from wrongfully accused or suspected individuals. The best wrongful conviction is one which never occurs.
10. Conclusion
Forensic evidence is based on objective data, which provides actionable information to investigators, including suspect identities and linking of similar crimes. Forensic evidence is perishable, in that its value diminishes over time. The majority of investigative costs are spent at the earlier stage of the investigation. Timely provision of objective forensic intelligence saves investigative resources, more accurately targeting investigations to the correct suspects, while effectively eliminating incorrect suspects from suspicion. When a backlog exists at the forensic laboratory, a large portion of time awaiting a forensic laboratory report is attributed to the case sitting prior to analysis, not the analysis itself. While starting the analysis as soon as a case is received provides maximum utility to the investigation, providing targeting analysis on high evidentiary value items is an interim step than can be provided immediately. Employing a 2-step screening and confirmation process using portable instrumentation, Rapid DNA and NIBIN provides actionable investigative leads for suspect elimination and inclusion, which are confirmed in accredited forensic laboratories for judicial proceedings.
The Proactive Crime Scene Response has several components, which include the major categories of communication, forensic scientist expert liaison, training, and education, streamlined analysis on high value evidentiary items and rapid reporting. Communication includes forensic laboratory notification of crimes that may have a forensic component, active outreach to responding crime scene investigators in real time with scientific expertise and dedicated forensic science expert liaisons. Ongoing education and training includes in-person and remote learning, webinars, short videos, handbooks, and cheat sheets. Streamlined forensic analysis ensures forensic laboratories have managed their analysis flow to start analysis immediately on high evidentiary value items with reduced impact on the standard evidence flow. Finally, streamlined reporting includes Laboratory Information Management System (LIMS) electronic reporting or other electronic means of providing results to investigators and justice system officials. LIMS can also provide collation of results to provide a larger picture of findings where MOUs between police agencies permits sharing of aggregate forensic laboratory compiled information and data.
Resources allocated to provide timely forensic analysis are well spent. Turnover of crime scene specialists and investigators and increasing forensic technology requires an ongoing education as to the best use of forensic science and the interpretation of results as they relate to the investigation. The proposed investigator-forensic scientist expert partnership proposed herein is a means to alleviate the risks of investigator turn-over and realizing improvements in rapidly evolving forensic technology and optimizes the value of forensic intelligence to the investigation. Quicker solving of crime, prevention of future crime and more timely elimination of wrongfully suspected dictate a proactive crime scene approach.
Declaration of competing interest
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:
The author collaborates with Dr. Igor Lednev, SUNY Albany and SupreMEtric. The author is the Chair of the National Institute of Standards and Technology (NIST) Forensic Science Standards Board (FSSB) of the Organization of Scientific Area Committees (OSAC) for Forensic Science.
Acknowledgements
The author wishes to express his appreciation for the outstanding quality of forensic service and dedication exhibited by forensic scientist experts at the former Royal Canadian Mounted Police Forensic Laboratory Regina, Canada; the Acadiana Criminalistics Laboratory, New Iberia, Louisiana; the Montgomery County Police Crime Laboratory, Gaithersburg, Maryland; and the New York State Police Crime Laboratory System and Forensic Investigation Center, Albany, NY.
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