Forensic Pathologist Testimony, Part 2: Special Issues and Considerations

Abstract

Introduction

Forensic pathologists routinely testify in courts of law as part of their occupation. As such, part of their training involves learning how to testify responsibly and competently. As experts, they are permitted to offer opinions in order to assist the triers of fact.

Results

This review examines such concepts as burden of proof by manner of death, mechanisms of death, survival intervals, and the differences between possibilities, probabilities, and reasonable degree of medical certainty. It also addresses legal concepts and issues that may arise in court, including those of pain and suffering, cognitive bias, objections, attempts at witness impeachment, and surrogate witness testimony, as well as a summary of pertinent case law.

Discussion

The special issues and considerations of the expert forensic pathologist are discussed with the aim to summarize some of the key issues that may arise in court for the forensic pathologist.

INTRODUCTION

Forensic pathologists routinely testify in courts of law as part of their occupation. Common questions and considerations in forensic pathology testimony have been previously addressed.^1–3 In addition to understanding the common opinions that a forensic pathologist may be asked to offer in court, there are other special areas and topics that the forensic pathologist may encounter.

We are aware of the potential to use this publication to impeach witness testimony. We can foresee the possibility of it being misunderstood, misused, or even weaponized at a trial. Therefore, as a preemptive strike, we add this caveat:

We cannot anticipate every variable and contingency that may exist in a specific case, one or more of which could reasonably contradict some of these guidelines. Forensic pathologists are rarely able to be 100% certain of an opinion, as doing so implies that there are no other (reasonable or unreasonable) possibilities. With that in mind, the use of this guide is best tempered by viewing it through the lens of experience, the recognition of nuance and context, physical and investigative, the expectation of occasional outliers, and the specifics of each case. There is rarely a one-size-fits-all paradigm that applies to forensic pathology practice.

DISCUSSION

Mechanisms of Death

Consideration of the mechanism of death is important in determining the proximate cause of death, as well as in addressing other questions that may later arise in relation to a given case. Penetrating injuries, especially those caused by sharp force trauma, typically cause death by blood loss (including exsanguination), tamponade (eg, cardiac, subdural hematoma), air embolism (eg, injury of jugular vein), pneumothorax/hemothorax, and/or extensive aspiration of blood into the lungs. Blunt force may produce similar sequelae from lacerated blood vessels, but injury mechanisms also include cerebrospinal injury (eg, DAI, spinal shock) and commotio cordis.^4–7 So-called asphyxial injuries cause death by cerebral hypoxia and/or ischemia (see “Asphyxia” in Part 1), as the brain is the most sensitive organ to hypoxemia or lack of blood flow.

When a death is related to blood loss, the FP is best advised to come to court armed with the knowledge of the formula for estimating total body blood volume (TBV), which is approximately 65 to 70 ml per kilogram of body mass in adults. In order to cause death, an otherwise healthy person typically must quickly lose 50% of their blood volume (similar blood loss over weeks or months would be less uniformly lethal, given the time span that allows for the body's compensatory mechanisms to kick in). Additionally, a lesser amount of blood, approximately 1/4 to 1/3 of TBV, is expected to result in shock. Therefore, and importantly, despite acute exsanguination, there is usually still some degree of blood in the vasculature at the time of autopsy. Still lesser amounts of blood volume may cause death not by a hypovolemic mechanism, but rather a compressive one, if the blood rapidly accumulates in a vital enclosed space (eg, cardiac restriction by a hemopericardial tamponade or cerebral compression by a rapidly expanding subdural or epidural hemorrhage or contusion hematoma). Moreover, poor cardiovascular and pulmonary health also may affect survivability, potentially decreasing the degree of blood loss necessary to cause death.

When there is hemorrhaging in the body, blood will flow to where there is the least resistance. If an internal organ such as the heart or the aorta is injured, blood will first accumulate in the surrounding accessible body cavities. Therefore, there usually is not a gushing of blood or extensive hemorrhage outside of the body unless the wound is gaping, there is no such cavity into which blood can collect (eg, such as occurs with injuries of the major blood vessels of the neck), and/or unless the body position is fixed is such a way that the wound is dependent and the blood flows with gravity. With injuries to the neck vasculature, on the other hand, there is nowhere for the blood to flow except out into the surrounding environment, including onto absorptive clothing or bedding materials, if present. External bleeding from the torso is also limited by the functional collapse of the wound track, abetted by the elasticity of the skin and the weight of the surrounding soft tissues. With movement of the body, however, blood may externally seep out of the wound both before and after death.

There also can be some degree of postmortem “bleeding,” more accurately referred to as passive seepage from blood vessels having no physiologic blood pressure, but still containing some preexistent (antemortem) residual blood, aided by the compressive pressure exerted by the weight of the surrounding tissues. This type of post/perimortal bleeding tends to be characteristically limited/minimal, for obvious reasons (little or no circulation from the death/dying process). This may be demonstrated from cardiac resuscitation attempts and explains why limited blood will ooze from a cut blood vessel during autopsy. Unless there is a prolonged hospital course and/or blood product replacement, an excellent marker to demonstrate extensive antemortem blood loss is visceral, muscular, and/or gingival pallor, which is physical evidence of (hypovolemic) shock, an intravital process. This understanding is particularly useful in cases where the degree of blood loss is physically less measurable (eg, external blood loss from a fatal incised wound of the neck or into a mattress), necessitating other physical evidence of exsanguination to be sought.

In addition to a hemorrhagic mechanism, fatalities related to firearms injuries may also result from the more immediate functional damage exacted by a bullet tearing through vital structures, such at the complex electrical circuitry of the heart or brain. In this setting, what is functionally, microscopically, and ultrastructurally damaged may far exceed what is grossly observed at autopsy (eg, the formation of a temporary cavity from a firearm injury), in contrast, for example, to a stab wound. As such, incapacitation (unconsciousness) and death may ensue much more rapidly, depending on the structures perforated (eg, heart, brain, aorta) than when the mechanism is purely exsanguination. The viscera, especially the kidneys, may still be strikingly pale in these instances, but from cardiogenic or neurogenic shock, not from hypovolemic shock, per se.

Delayed deaths from remote injuries (see below), depending on the modality, may eventually cause death by such immediate causes as infection, bowel obstruction (adhesions), seizures in the setting of a post-traumatic seizure disorder, or complications of paralysis (eg, urosepsis, decubitus ulcers), to name only a few.

Finally, it is important to remember that in certain more complex fatalities, such as some related to restraint or that require descriptive cause of death statements, there may not be just a single mechanism that links the cause of death with the moment of death. Rather, there may be a complex interplay of multiple mechanisms that occur either contemporaneously or in sequence, some or all of which may be sequelae of the primary/proximate cause of death or secondary, stand-alone conditions. There is no dictum in forensic pathology that limits a fatality to a single mechanism or immediate cause, despite the fact that in many, there is only one predominant and overwhelming pathophysiologic insult that eclipses and renders moot all others (eg, hypovolemic shock from acute exsanguination, perforation of the brainstem by a bullet, or a saddle pulmonary thromboembolism).

Neglect

Criminal neglect is seen in various situations in which an individual who is dependent upon the care of another fails to thrive in any number of ways, sometimes fatally. This most typically involves pediatric and elder abuse, but also is encountered with some adult persons, over a range of ages, who have various degrees of dependent disability. The establishment and careful documentation of the decedent's dependency, the degree and scope of the neglect, the medical record, if available, as well as the cognitive and psychologic aptitude of the caregiver all typically become both important and relevant in the death certification and adjudication of these cases.

One type of pediatric neglect involves starvation and dehydration.^8–15 These children are often markedly cachectic. It is not unusual for a defense counsel's expert to opine that an underlying malabsorption syndrome was missed by the autopsy pathologist.^15,16 Even if this is possible, it may not absolve the caregiver of their neglect. If the child never received medical care and was allowed to wither to this cachectic state, one that any reasonable person would have recognized, then there is neglect. A simple photograph of the child in this debilitated state makes it clear how any reasonable person would recognize that this child needed immediate medical care and yet did not receive it.

Delayed Deaths Following Remote Injury

Two issues commonly arise in expert testimony dealing with delayed deaths related to remotely sustained injuries, whether mechanical or chemical. The first is the proximate cause of death. To wit, one must establish a direct pathophysiologic link between the initial injury and the moment of death, an interval which may span up to decades. This pathway typically involves the careful identification of mechanisms and immediate causes, such as an infection (eg, bronchopneumonia or a urinary tract infection/urosepsis), along with the equally important identification of the accurate and uninterrupted link between those and the injury that initiated the lethal sequence of events (the proximate cause). Attorneys may focus on the immediate cause of these death (eg, pulmonary thromboembolism) and neglect to address the underlying (proximate) cause of death. The proximate cause of death is the etiologically specific disease or injury, which in a natural and continuous sequence, unbroken by any efficient intervening cause, produces the fatality and without which the fatality would not have occurred. Therefore, one must consider if there is an efficient intervening cause that removes the remote trauma as the proximate cause.

The second issue is whether there are one or more contributing conditions (part 2) that may have played a role in the death, so important in explaining the death that they cannot be reasonably ignored. Such conditions do not exculpate the primary injury in part 1, but they may spread the burden of causality a bit more widely.

Survival Intervals and “Pain and Suffering”

A survival interval estimate reflects the time course that would reasonably be expected to elapse between the time of injury occurrence and the moment of death, if the injury is not contemporaneous with it (such as is the case with many/most brainstem transections) or when it is not known through credible witness observations, video surveillance, and/or a hospitalization. A subset of the survival interval could be referred to as the potential “activity interval,” an estimate of the degree of purposeful activity and movement, even if progressively waning, that might be reasonably expected during the survival interval, prior to the onset of unconsciousness and death. Both intervals will vary depending upon the type and extent of injury (see “Firearms” in Part 1 of this series) and are based on the forensic pathologist's expertise of injuries and how they would be expected to manifest pathophysiologically and behaviorally. ¹

Pain and suffering questions may arise in criminal and, much more commonly, in civil proceedings.^17–20 In criminal cases, the establishment of pain/suffering and/or permanent damage may affect criminal charges. In civil matters, such as in wrongful death lawsuits, if the plaintiff prevails, the degree of established pain and suffering is typically proportionate to the defendant's liability and, therefore, commensurate with the monetary damages.

To that end, the forensic pathology expert witness may play an important role, depending on the specifics of the case. As physicians who are experts in injury and its myriad of pathophysiologic sequelae, forensic pathologists are often positioned to opine about the degree and quality of pain that a given injury would be expected to produce in the average, conscious, and sentient individual, with emphasis on conscious (see below). The suffering aspect may logically dovetail with the pain, but given that it is less measurable and more variable from person to person, it becomes an assessment the jury is more likely to come on their own, after careful review of all of the evidence presented in the case, including medical testimony, witness statements, their own personal experience, and common sense. A forensic pathologist, for example, can reasonably and medically explain the degree of pain and immediate immobility a compound, comminuted fracture of the femur would, in overwhelming likelihood, cause, or what the sensation of “air hunger” feels like (fear, panic, extreme discomfort/distress), such as occurs during the conscious interval of a smothering. They might also help to clarify how the perception of visceral injury is qualitatively different than the perception of injury to the exquisitely sensitive human skin.

All that said, however, the most important foundational question upon which the above opinions are based is predicated on the likelihood of an individual's consciousness in the face of the specific injuries in question. This is because people who are unconscious do not feel pain (this is why surgery is performed on unconscious persons), making a discussion and opinions about pain and suffering in unconscious people moot. As such, for any pain and suffering inquiry, the question of likely consciousness and conscious awareness should be addressed first and foremost.

The autopsy is able to offer greater or lesser degrees of evidence regarding the length and likelihood of an individual's consciousness based on the extent and type of their injuries. For example, a femur fracture would not be expected to cause immediate unconsciousness, unless an immediate pain-induced cardiac arrhythmia ensued (such as in a person with advanced heart disease)—the latter easily ruled out by the identification of a survival interval supported by a vital reaction (substantial fracture-related hemorrhage), with or without witness observations. Similarly, a traumatic abdominal aortic transection would not necessarily be expected to cause immediate unconsciousness, but given the size of the aorta, would likely be associated with a much shorter conscious survival interval than that of a femur fracture. By contrast, a transection of the brainstem or marked diffuse axonal injury is immediately incapacitating, if not immediately fatal, and also rapidly/immediately causes unconsciousness. Other kinds of head trauma (one or more head impacts resulting in a skull fracture and subdural and subarachnoid hemorrhages) might also be immediately incapacitating through a concussive mechanism, but not uniformly so (ie, these injuries may also be reasonably associated with a lucid interval). In such a circumstance, investigative data points, such as observations from witnesses and/or emergency responders may help further elucidate the survival and consciousness intervals. This is why, in isolation, the autopsy may not always answer the consciousness question, but does at least typically add important data points to that end.

Strategies to Impeach an Expert Witness

On cross-examination, there are several strategies that can be used to attempt to impeach the testimony of an expert witness. These include: offering a learned treatise that contradicts the expert's stated opinion, pointing to prior statements of the expert in other proceedings that are viewed as inconsistent (n.b., there are national databases of prior expert testimony), highlighting financial interests, and alleging biases. To consider a learned treatise as authoritative, the witness must have read it in its entirety and agree with everything in it. If this is not the case, then it is most prudent for the witness to state they do not consider it authoritative, per se, even though it may be a popular or a commonly used textbook. If the expert witness is unfamiliar with it and the attorney gives them a copy, it would be reasonable for them to state that they would need time to read it in its entirety in order to formulate an opinion. If an attorney takes a statement from a journal article or textbook, the expert is well-advised to ask to see the reference to understand the context of the quoted statement, given that the unread next line may say, “But in the vast majority of cases, this is not so.” In addition, when reviewing any material at trial, the expert should note the year of the reference and whether it is the most recent edition available.

Cognitive Bias

Cognitive bias represents an unconscious limitation in reasoning, evaluating, remembering, and/or other cognitive processes, that often occur as a result of holding onto one's preferences and beliefs regardless of the existence of contrary information. Forensic pathologists, like attorneys, jurors, and judges, are not immune to cognitive bias.^21–23 Confirmational bias is the tendency to search for or interpret information in a way that confirms one's preconceptions. Contextual bias occurs when extraneous information influences a decision (history and circumstances).

Forensic pathology is a subspecialty of medicine and context cannot be removed from medical practice, despite the fact that the field of medicine recognizes the problem of cognitive bias.^24,25 Regardless, physicians can only reliably confirm or refute hypotheses by gathering historical and contextual evidence (eg, interviewing a patient or witness, reviewing medical or other official records, conducting a scene investigation), performing physical examinations (eg, taking a blood pressure, performing an autopsy), and using diagnostic studies (eg, toxicology testing, hematocrit quantitation) to formulate medical diagnoses. Historical and circumstantial information is also necessary to determine whether a case even falls under medicolegal jurisdiction and, if so, whether an autopsy is warranted.

Qualified Immunity

Qualified immunity protects a government official from lawsuits alleging that the official violated a plaintiff's rights. It would only allow such suits to proceed when officials violated a “clearly established” statutory or constitutional right. When determining whether a right was “clearly established,” courts consider whether a hypothetical reasonable official would have known that the defendant's conduct violated the plaintiff's rights (see below, Ferris V. City of Cadillac). For forensic pathologists, case law has shown them not to be liable for the good faith expression of an opinion based on accurate medical information. ²⁶

Objections: Overrule and Sustain

An objection is a formal protest voiced by an attorney to a judge to disallow a witness statement. In response, a judge will sustain or overrule the objection. If an objection is sustained, it means that the judge agrees with the objection and disallows the answering of the question. By contrast, if the objection is overruled, the judge disagrees with the objection and allows the witness to proceed in answering the given question. There are a variety of situations (“grounds”) that may lead to an objection. These include: leading questions, hearsay testimony (there are exemptions), assuming facts that are not in evidence (as may occur with hypothetical questions), badgering of the witness, relevance or vagueness of the question, questions that have already been asked and answered, speculative questions or answers, argumentative questions, nonresponsive answers, compound questions, or questions that lack a foundation. Regardless of its grounds, when an objection is raised, the witness, expert or fact, is best advised to sit quietly until the judge turns to them with an instruction either to answer the question, asks the witness a clarifying question before making a ruling, or tells the witness not to answer the question and to wait for the next one.

Degrees of Certainty

There are various degrees of certainty and different types of opinions. ¹ The degree of certainty needed for the forensic pathologist to testify to an expert opinion and to certify the cause and manner of death is more than a mere possibility. The death certificate is a legal document that is based on probability. For natural and accidental deaths, a simple probability is required (that is, more likely than not). Such a burden of proof (referred to legally as “preponderance of evidence”) is also the requirement set for opinions in most civil proceedings.

For homicides (and usually for suicides), on the other hand, most forensic pathologists require a higher degree of certainty than simple probability (>50%). The common term for this is “reasonable degree of medical/scientific certainty” and it far exceeds the 51% mark. It is the degree of certainty achieved when there is no other reasonable possibility/explanation for the death. Forensic pathologists are never held to a 100% certainty and must be careful not to routinely testify to 100% certainty. Such an assertion would mean that there is no other reasonable or unreasonable possibility, and there are few medical opinions that can meet that burden. All that said, many judges do not permit the “reasonable degree of medical or scientific certainty” parlance into their courtrooms, instead having the expert simply assert their opinion without attaching a level of certainty to it.

Finally, there are two types of forensic opinions: investigative and certified. Investigative opinions and statements may involve possibilities and developing theories in the investigation during its early stages, some of which may be documented in the case file by the medical examiner and/or the medicolegal death investigator. Some reports may memorialize information communicated during law enforcement discussions at a preliminary stage when there may have been incomplete investigative or laboratory information. While it is common practice to document such information in the case file along the way, these preliminary opinions or statements may differ from the ultimate and final opinion later asserted by the forensic pathologist, so they may be presented to the expert witness to explain and defend in court. The expert witness need not apologize for nor fear or deflect those questions. Rather, these preliminary statements can and should be contextualized and clarified as what they represent: transparent and assiduous documentation, standard practice in evolving forensic investigations.

By contrast, certified opinions represent final conclusions that reflect consideration of all available facts, medical, physical, and investigative, and that are memorialized on a death certificate and/or under oath. These certified opinions meet degrees of medical certainty greater than a possibility. Finally, it is important to point out that the only correct (honest) answer in response to certain questions may be a simple, “I don’t know.” There is nothing improper in giving this answer. To the contrary, this response acknowledges that all expert witnesses have limitations in the scope of their knowledge, and/or that the answers to some questions are simply “unknowable” no matter the level of experience or knowledge. In the end, telling the truth is always the right decision.

Surrogate Testimony

There are instances in which the forensic pathologist who performed an autopsy is unavailable to later testify at trial. The issues surrounding the court's acceptance of surrogate testimony (testimony given by an expert witness on behalf of another who is otherwise unavailable), primarily in homicides, have undergone changes over the past several years, in both Federal and State jurisdictions (see “Summary of Case Law” below). Despite the differences among jurisdictions, which are currently in a state of flux, there are some practices that might be put into place that may help facilitate the acceptance of surrogate testimony. This starts at the autopsy table. Rigorous and thoughtful photographic documentation (see below) of the external and internal injuries provides objective and documentative information (pertinent positive and, sometimes, negative findings) that will assist the surrogate expert in forming their own independent opinion. At trial, the surrogate forensic pathologist should make clear that they are basing their independent opinions on their own knowledge and expertise, as well as on their review of multiple materials, not just the autopsy report alone. In addition, it should be noted that the methods and data upon which their opinions are based are of the sort considered reliable in the field and that the opinion is connected and relevant to the case.

The Supreme Court's decision in Arizona v. Smith instructs that each court should determine whether a statement is testimonial by looking at the “primary purpose” for which the statement was made. The term “testimonial” has never been specifically defined by the Supreme Court, but the Smith decision follows prior Supreme Court decisions that indicate that the term “testimonial” means focused on, prepared for, or reasonably expected to relate to future court proceedings. The Supreme Court's decision disallows surrogate witness testimony that is based solely on another professional's “statements” (eg, reports, notes, and testing documents) if those statements are deemed “testimonial.” The Smith decision similarly implies that we cannot testify for our unavailable colleagues on their cases in circumstances where the autopsy report is deemed testimonial, as defined by the Supreme Court by precedent.

The Smith decision does not settle the legal question about whether the entire autopsy report (not just the cause and manner opinion statement) is testimonial. Most objective descriptions documented in an autopsy report (except for height, weight, age, etc) require a level of expertise that the average person does not have. Therefore, one could argue that the objective descriptions themselves (eg, those of an entrance vs an exit wound) are actually subtle expert opinions. These same objective descriptions and opinions, however, may be given and reached, respectively, based on autopsy photographs (usually, the more pertinent, documentative photographs there are, the better).

The autopsy report is largely a medical record, which primarily documents the observed autopsy findings, including a detailed description of all disease(s) and/or injuries. In light of the Court's decision, it is important that attorneys and courts understand that medicolegal autopsies are medical procedures within the larger practice of medicine. In addition, most autopsy reports include a final cause of death opinion (rendered by the autopsy forensic pathologist), the same opinion as that found on the death certificate. It is this opinion statement with which the surrogate witness neither expressly agrees nor disagrees, per se, during their testimony. Rather, they assert their own independent conclusions and opinions, opinions that are based on their training and experience, their review of the objective autopsy findings, and the accompanying documentative photographic record of same, radiographs, if taken, microscopic evidence, if any, and relevant investigative information.

Surrogate witnesses can testify from the photographs, as they are not generally considered testimonial, but rather “raw data,” much like the data represented in a graphical mass spectrometry report. Photographs may come in as evidence in two ways. The first is as a business record from someone qualified (ie, present in the organization at the time the photographs were taken and competent to testify to the business practices). The second way they may be introduced is through someone who was present (this does not have to be an employee of the agency, per se, so could include a detective), as long as they can say the photographs are a “fair and accurate representation of the examination findings they depict.” The surrogate expert then testifies from the photographs, without wholly relying on the report, although, if necessary, could answer questions as to whether the descriptions found in the report are consistent or inconsistent with those objectively observed in the autopsy photographs.

In some jurisdictions, listing other forensic pathologists as supervisors, assistants, or otherwise being in attendance during an autopsy may provide an additional basis for the surrogate expert to testify, but they must still provide their own opinion and only their opinion. Importantly, care should be taken in distinguishing the entire medical examiner/coroner (MEC) case file, which may include initial investigational information (such as a reference to a suspect/person of interest, per authorities) from the separate and final autopsy report, the latter a document included within the larger case file, but that is often the only document in that file authored by the physician who performed the exam. Without this clarification, there is a risk for conflating the two (see Garlick v. Lee, 1 F. 4th 122 (2d Cir. 2021)). Documents not prepared by the forensic pathologist or by someone else in the same organization with the same duty to prepare their entries contemporaneously with the events, however, are not admissible as a business record. For this reason, the expert cannot base an opinion on the latter documents.

MEC are neutral arbiters and finders of fact, and many stakeholders may be interested in what they ultimately discover. For that reason, medicolegal autopsies, in contrast to hospital autopsies, often involve much more extensive and rigorous photographic documentation, which is stored as evidence, in part, to afford various third parties, including defense and plaintiff experts, as well as surrogate expert witnesses, the opportunity to objectively and independently review the preserved visual record of the pertinent negative and positive gross (and sometimes microscopic) findings long after the autopsy has been performed. This standardized, documentative system is put in place not only for third parties but also for the forensic pathologist who performed the autopsy. Given the number of cases most forensic pathologists autopsy, and the fact that months, years, and even decades (the latter in some cold case homicides) may have passed before post-autopsy criminal or civil litigation comes to fruition, the autopsy-performing forensic pathologist rarely, if ever, has an independent and comprehensive recollection of the granular details of a given fatality, much less of the thought processes that led them to their conclusions at the time. Rather, when preparing for a trial, they too, like surrogate, plaintiff, and defense expert witnesses, must rely upon the well-documented, objective record of findings (notes, autopsy report, autopsy and scene photographs, radiographs, microscopic slides, toxicology reports, etc), as well as investigative reports, to again come to reasonable and evidence-based interpretations and conclusions at the time of the trial.

Finally, in most jurisdictions, police/law enforcement officials are legally required to notify the MEC of any out-of-hospital deaths that are apparently traumatic, toxin/drug-related, or otherwise suspicious (among other categories), and the MEC is statutorily required to investigate those deaths, irrespective of the interests of police and/or other outside parties in having or not having an autopsy performed. Indeed, the deaths that a typical MEC office investigates are not homicides. Moreover, most MEC operate separately and independently from law enforcement and are more closely associated with the public health system. As such, autopsy reports are prepared as a normal business record, not by edict of law enforcement officials or the criminal justice system, although MEC do recognize that their certified reports may be used in both civil and criminal justice matters. As stated above, perhaps most accurately described, the MEC autopsy report is a medical record, which is prepared by a physician, just as is a hospital autopsy report or a hospital surgical pathology report that describes a colon cancer that was removed by a surgeon.

CONCLUSION

This review discusses special topics, such as mechanisms of death, survival intervals, issues of neglect, burdens of proof, and the differences between possibilities, probabilities, and reasonable degree of medical certainty. It also addresses legal concepts and issues that may arise in court, including those surrounding pain and suffering, witness impeachment, cognitive bias, objections, and surrogate witness testimony, as well as a summary of pertinent case law.

Arguably, the primary focus of any expert witness should be on testimony content. Specifically, this refers to the accuracy and veracity of their testimony and opinions, and the delivery of those opinions in truthful and plain language, even if not conveyed with the advantage and polish of years of experience. That said, understanding the courtroom, its cadence, its language, its players, and its rules of engagement will place forensic pathology expert witnesses in a much more advantageous position to assert their opinions from a less cluttered headspace and to address their important task without needless distractors and threats to their credibility. Indeed, being familiar with and prepared for the above-described procedural detours and caveats will position them to be more neutral, effective, and helpful participants in criminal justice and other legal proceedings. They have an important job to do, but they have no dog in the fight.

SUMMARY OF U.S. CASE LAW

Daubert v. Merrell Dow (509 U.S. 579 (1993)): The Daubert standard is a rule of evidence regarding the admissibility of expert witness testimony. A party may raise a Daubert motion, a special motion in limine raised before or during trial, to exclude the presentation of unqualified evidence to the jury. The guidelines include: the judge as the gatekeeper, the testimony is relevant and reliable, using sound scientific methodology.

Frye v. United States (293 F. 1013 (D.C. Cir. 1923)): A judicial test used in some state courts to determine the admissibility of scientific evidence. It provides that expert opinion based on a scientific technique is admissible only when the technique is generally accepted as reliable in the relevant scientific community. In Daubert, the U.S. Supreme Court held that the Federal Rules of Evidence superseded Frye as “the standard for admissibility of expert evidence in federal courts.”

Melendez-Diaz v. Massachusetts (557 U.S. 305 (2009)): The court found that it was a violation of the Sixth Amendment right of confrontation for a prosecutor to submit a chemical drug test report without the testimony of the person who performed the test. This has since been applied to the autopsy report.

Bullcoming v. New Mexico (564 U.S. 647 (2011)): The Supreme Court considered the issue of whether a defendant's Confrontation Clause rights extend to a non-testifying laboratory analyst whose supervisor testifies as to test results that the analyst transcribed from a machine. The Court held that the second surrogate analyst could not testify about the testimonial statements in the forensic report of the certifying analyst under the Confrontation Clause.

Williams v. Illinois (567 U.S. 50 (2012)): The Court affirmed that the testimony of an expert witness that is based on a test the expert did not personally perform is admissible and does not violate the defendant's rights under the Sixth Amendment Confrontation Clause, if it was not offered to prove the truth of the matter asserted, but merely to provide a basis for the conclusions that the expert reached, so the prosecution had not infringed on the defendant's rights. Additionally, such a test does not fall within the bounds of the Confrontation Clause if the test was not conducted or performed to prove the guilt of the defendant.

Smith v. Arizona (22-899): This case addressed the issue of whether the Confrontation Clause of the Sixth Amendment permits the prosecution in a criminal trial to present testimony by a substitute expert conveying the testimonial statements of a non-testifying forensic analyst.

A surrogate forensic pathologist cannot testify to the autopsy report prepared by the forensic pathologist who performed the autopsy if the report's “statements” constitute testimonial hearsay which has two parts: “testimonial” and “hearsay.” An autopsy report constitutes hearsay if the testifying forensic pathologist's opinion is formulated based on the truthfulness and accuracy of the initial autopsy report. In other words, Smith advises that if statements in the autopsy report written by the performing forensic pathologist must be true and accurate for the second forensic pathologist to have valid information on which to base his or her testimony, the autopsy report is hearsay.

To determine whether a statement is “testimonial” per the Smith decision, trial courts are to engage in a two-step process. First, they must define what is to be relied upon by the testifying expert. “Exact statements” to be identified for the primary purpose determination will include the autopsy report, but will also include correlating documents, reports, and autopsy diagrams. Second, each trial court must then determine the “primary purpose” for each. Courts must determine, given all the relevant circumstances, the principal reason or purpose for which the statement or statements were made.

Burrage v. United States (571 U.S. 204 (2014)): A defendant cannot be liable for penalty enhancement under the Controlled Substances Act unless such use is a but-for cause of the death or injury, at least when the use of a drug distributed by the defendant is not an independently sufficient cause of the victim's death or serious bodily injury.

Ferris v. City of Cadillac (272 F.Supp.3d 1003 (2017)): The decision stated that “The Court is aware of no Circuit case that exposes a forensic medical examiner to liability for the good faith expression of an opinion based on accurate medical information. The record here shows nothing more, and Defendants are entitled to qualified immunity.”

Crawford v. Washington (541 U.S. 36, 59): The Supreme Court held that the confrontation clause permits admission of “testimonial statements of witnesses absent from trial…only where the declarant is unavailable, and only where the defendant has had a prior opportunity to cross-examine and as long as the defendant had the same interests in that prior opportunity as he does in the current case.”

Glossary of Terms Commonly Encountered in the Legal Proceedings

BURDEN OF PROOF: The duty of producing evidence. In a criminal case, the burden of proof begins and remains always on the prosecution and is always “beyond a reasonable doubt.” In civil cases, the burden begins with the plaintiff once the plaintiff has sustained the burden, and has shown a prima facie case, the burden shifts to the defense. If the defense does not rebut the plaintiff's case, judgment shall be entered against him. If the defense does rebut the case, then the burden shifts back to the plaintiff, at which time the plaintiff once again produces evidence, or the case goes to the jury.

COURT'S WITNESS: A witness called into court by the judge, rather than by one of the parties. This occurs where the Judge feels that both parties have failed to call a witness who obviously has knowledge of the case and where his absence may cause an injustice, or more commonly where the court desires expert testimony in a case where the parties have offered none. In such cases, both parties may cross-examine the expert.

AUTHENTICATION: Proof that an item offered into court is in fact what the proponent say it is; it is the testimony that connects the item to the issues of the lawsuit. Thus, if the prosecution in a concealed weapons case wants to offer the weapon itself into evidence, testimony will have to be offered which identifies that a particular weapon as the one which the accused concealed. Such proof is easily secured where the item in question is easily recognizable (serial numbers on a pistol; scratch marks made in a knife blade at the time of seizure) but may be more difficult where the item is not itself readily distinguishable from other items of its type (eg, a blood sample, white powder containing heroin); in these cases, the “chain of custody” (see below) is employed.

CHAIN OF CUSTODY: Proof of the whereabouts and handling of an item from the time of its seizure until being offered into court. Certain items offered into court are not readily distinguishable from other items of their type, such as a sample of body fluid or a white powder alleged to contain heroin. To “authenticate” the evidence, it is often necessary to introduce evidence from everyone who had custody over the item in the form of a “chain.” This will satisfy the requirement that the proponent offers proof that the item is the same item that was seized. If the nature of the item is itself in issue (blood level of alcohol, presence and/or absence of heroin in a powder), testimony showing that the item was not tampered with from the time of its seizure until it arrived in the testing laboratory is also necessary. This latter proof may even be necessary where the item itself is easily recognizable, but a certain quality of the item is in issue (ability of a given pistol to fire a certain type of round, whether the substance on a knife blade is human or animal blood, etc). It is often the case, however, that the chain of custody may also be proven by evidence of the regular course of business of the institution or organization that had custody of the item.

CIRCUMSTANTIAL EVIDENCE/DIRECT EVIDENCE/INDIRECT EVIDENCE: Direct evidence is evidence of a fact based on a witness's personal knowledge or observation of that fact. Circumstantial evidence is direct evidence of a fact from which a person may reasonably infer the existence or non-existence of another fact.

Thus, if the question is whether there were rabbits in the field, testimony that an individual has seen rabbits there is direct evidence. Testimony that an individual has seen rabbit tracks in the field is circumstantial evidence. The tracks are not the issue, but evidence of them does tend to resolve the ultimate issue of the presence of rabbits.

A person's guilt of a charged crime may be proven by circumstantial evidence if that evidence, while not directly establishing guilt, gives rise to an inference of guilt beyond a reasonable doubt. That inference must be the only one that can fairly and reasonably be drawn from the facts, it must be consistent with the proven facts, and it must flow naturally, reasonably, and logically from them.

It should be noted that direct evidence is not necessarily stronger than circumstantial evidence, and that, in fact, the reverse is often true. A case may be based on both types of evidence or entirely on one or the other. The law draws no distinction between circumstantial evidence and direct evidence in terms of weight or importance. Either type of evidence may be enough to establish guilt beyond a reasonable doubt, depending on the facts of the case as the jury finds them to be. Most scientific evidence is circumstantial in nature.

CONTINUANCE: Rescheduling of court trail, hearing, etc.

CORPUS DELICTI: (1) The fact that a crime was committed as separate from proof that any given person committed it. Thus, in a murder trial, the state must prove that the victim is indeed dead, and that he was murdered. (2) The body or material substance upon which a crime has been committed, eg, the corpse of a murdered man, charred remains of a house burned by arson.

CRIME: An act or omission in violation of a public law that provides penalties upon conviction, violations are prosecuted, in the name of the offended government, in what are known as “criminal proceedings,” in which the rules are similar, but not identical to those in civil actions.

CIVIL ACTION: Lawsuit in which one seeks recovery or the establishment of private rights. Suit where one seeks redress or prevent private wrongs. Normally, these suits are between private parties, although governments and corporations may sue in their own name; they are to be distinguished from criminal actions, where a defendant is accused by the government of the violation of a penal law.

DEGREES OF CERTAINTY: There are different types and degrees of certainty regarding medical opinions. For types of opinions, there are investigative and testimonial. Investigative opinions may involve possibilities as the investigation is in an early stage with incomplete information. The degree of certainty needed for the forensic pathologist to testify to an expert opinion and to certify the cause and manner of death is more than a possibility. For natural and accidental deaths, a probability is required (that is, more likely than not). For homicides (and usually suicides as well), most forensic pathologists require a higher certainty than a probability. The common term for this is a reasonable degree of medical certainty. It is the degree of certainty when there is no other reasonable possibility. Forensic pathologists can never be held to a 100% certainty and must be careful to not testify to 100% certainty. This would mean that there is no other reasonable or unreasonable possibility. There are few medical opinions that can meet that burden.

DEPOSITION/INTERROGATORY: During the discovery process in a civil trial, it often becomes necessary to take sworn statements from witnesses, including the opposing parties. In the case of a deposition, the witness is summoned to an office where he is questioned by one attorney and cross-examined by the other, and a verbatim record is made which is examined and sworn to by the witness. Interrogatories are a less formal method of discovery, whereby one party sends a list of questions to the other party or witness. The witness then answers the questions (in writing), signs the document, and returns them to the sending party. Both procedures are a matter of right, and refusal of a witness to cooperate can result in him being held in contempt. If the recalcitrant witness is a party to the suit, his refusal can result in automatic judgment against him. Neither method is used to any great extent in criminal cases, although defense attorneys sometimes do utilize them.

DISCOVERY: Discovery is the formal method by which evidence is exchanged by the parties to a suit prior to the actual trial. In civil actions, discovery is quite broad and includes depositions, interrogatories, the right to investigate records, make examinations of physical evidence, take appropriate photographs, etc In criminal actions, discovery is often equally broad, especially in those jurisdictions that have expanded discovery in criminal actions to include the expert's notes and reports, as well as their emails and disciplinary actions, if any.

EXCLUSIONARY RULE: In recent years, the Supreme Court of the United States has held that evidence taken in violation of an accused's rights may not be presented in evidence; thus, the Court has “excluded” it. The rationale is that by not allowing the Government to use illegally obtained evidence, the police will be less likely to engage in conduct violative of an individual's rights.

It should be noted that the rule applies only to evidence taken by the government or its agents and applies only to evidence offered in criminal trials.

EXPERT WITNESS: Witness who is skilled in some art, trade, profession, or science or who has had specialized training or experience in relation to matters which are not generally within the knowledge of men/women of common education and experience. The significance of the expert witness is that they may give an opinion on a matter which is within his specialty, and which is involved in the inquiry, whereas the normal (fact) witness may generally state only what they have observed or done.

The expert may testify on matters within their specialty that they have tested or observed (a pathologist giving results and meanings of tests on a tissue sample), or they may answer hypothetical questions based on facts already introduced in court or that will be introduce later. They may not, however, testify on the “ultimate issue” before the court; this is true even where their testimony may seem dispositive of the case. Thus, a forensic pathologist may testify that the death of someone was not a suicide, but rather homicide, that the victim died of a certain type of injury inflicted in a certain manner, and that but for these injuries he would not have died. They may not testify that the deceased was murdered or that the accused is guilty of any given crime, as these are legal conclusions that are to be made by the court.

One should also note that experts are cross-examined on all aspects of their testimony, including their qualifications as experts; many courts allow cross-examination on this issue prior to his being allowed to give any expert opinions or conclusions.

FELONY/MISDEMEANOR: The distinction of felony and misdemeanor varies from state to state, but in general, felonies involve offenses for which the punishment includes confinement in a penitentiary or in death, other crimes being misdemeanors. Many states simply hold that the crimes punishable for imprisonment for one year or more are felonies, and that the rest are misdemeanors. Conviction of a felony often carries accessory punishments, such as the loss of voting rights, ineligibility for various licenses, etc.

HEARSAY: A statement which is offered into court to prove the truth of the matters asserted therein, but which was not made by the author when a witness is at the trial; it is normally inadmissible. Such statements may refer to documents as well as oral statements; hearsay also encompasses nonverbal conduct if intended by the person to be a communication. Basically, the rule says that a party to a suit cannot prove if a fact is true by showing that someone who is not present in court says it is. The basis for the rule is the right of the opposing party to cross-examine all of the witnesses against him. Medical records may be allowed as a business record.

IMMUNITY: The right to be free from prosecution for certain offenses, depending on the type of immunity. Immunity can be granted by a government, in which case the recipient can be forced to testify on the crime for which the immunity was granted and they no longer have the constitutional privilege to refuse testimony because they no longer could incriminate themselves.

INDICTMENT/INFORMATION: If the accusation listing the charges is presented to a court by a grand jury, it is an indictment. In the case of a grand jury, there is a closed proceeding before the grand jurors at which testimony is taken before the indictment is issued. If the accusation is presented by some government officer who is empowered to bring a criminal accusation to court without a grand jury, it is an information.

INDIRECT EVIDENCE is synonymous with circumstantial evidence.

INQUEST: The judicial inquiry made by a jury summoned for the purpose. The inquiry of a coroner, termed a “coroner's inquest,” involves the manner of death of anyone who has been slain or has otherwise apparently died in a manner that makes a coroner's inquest necessary.

INJUNCTION: A writ issued by a court directing a party to cease a certain activity. Technically, an injunction can only order someone to stop doing something, as opposed to ordering them to do something. However, courts often issue “negative injunctions,” which prohibit a party's failure to take a certain action and order affirmative action.

JURISDICTION: The authority under which courts and judicial officers act/the legal right by which these persons and offices exercise authority. Thus, a court of Criminal Sessions has no jurisdiction to grant a divorce, nor does a justice of the peace or magistrate have jurisdiction to try felony cases. Also, the term is used to denote a political subdivision wherein an officeholder has authority. The jurisdiction of an office or court is usually set out in the statute setting up that particular office or court.

LESSER INCLUDED OFFENSE: To prove a criminal offense, the prosecution must prove the existence of certain facts that together make up the crime; these facts are the elements of the offense. Thus, to prove a larceny, the state must prove that the accused (1) wrongfully (2) took, obtained, or withheld the (3) property (4) of another (5) with the intent to permanently deprive the owner thereof. The offense of wrongful appropriation consists of elements identical to those of larceny except that element five is absent. Thus, in proving larceny, the government automatically proves a wrongful appropriation, and it is said that wrongful appropriation is a “lesser included offense” of larceny. The same analysis would hold for murder and assault, and for almost any crime and the attempt to commit that crime.

Its importance is twofold: first, many accused persons plead guilty to a lesser offense in return for a lighter sentence; secondly, if the case goes to trial and the prosecution proves some, but not all of the elements of the offense charged, the accused will be acquitted of the charge, but may be convicted of the lesser charge if its elements were proved.

MENS REA: A guilty mind or purpose; a criminal intent. Guilty knowledge or willfulness. One of the elements of most crimes that must be proved by the prosecution.

MISTRIAL: An erroneous trial, a trial of an action which cannot stand as legal because of some fundamental error. In common parlance, the trial judge declares a mistrial when, in his opinion, some error has occurred that cannot be cured within the same trial, such as by a special instruction to the jury. For example, if the government introduced a confession before the jury when the confession was taken illegally, the judge must stop the trial and the trial must begin over again with a new jury. Mistrials are uncommon when a case is tried without a jury.

PETIT JURY: The jury that physically sits and hears a case during the trial, as opposed to a grand jury, which votes on indictments. In most jurisdictions, the petit (or trial) jury has 12 members for felonies and 6 for misdemeanors. The number of grand jurors differs by jurisdiction, but generally, has anywhere from 21–25.

PROBATIVE VALUE: The weight of a piece of evidence; the degree to which a piece of evidence helps to resolve the factual issue at hand. Evidence whose probative value is slight and whose presentation is extremely time-consuming may properly be excluded by the trial judge. (See prejudice prejudicial effect).

PLEADINGS: Pleadings are the formal allegations by the parties of their respective claims and defenses. They are made in writing and submitted to the court prior to trial. In the pleadings, the parties decide which issues they agree on, and which issues will have to be tried in court.

PREJUDICE/PREJUDICIAL EFFECT: Anything entering a lawsuit that causes bias on the part of the trier of fact is prejudicial. The amount of the prejudice constitutes the prejudicial effect. Evidence may be excluded if, in the judgment of the judge presiding, its probative value is outweighed by its prejudicial effect. The ruling is always made by the discretion of the judge. Thus, photographs of a murder victim may in fact help the trier of fact in deciding the manner and cause of death, but if unduly gruesome, they may be excluded on the basis that their prejudicial effect outweighs their probative value. Evidence of the manner of death will then have to be introduced in another way.

PRIMA FACIE CASE: A case where legal and competent evidence has been supplied on every element of the offense or case; such a case will support a finding in the proponent's favor unless contradicted and overcome by other evidence. The prosecution in a criminal case or the plaintiff in a civil matter must present at least a prima facie case before the judge will allow the case to go to the jury for a decision if a jury is sitting in that case. In the absence of a prima facie case, the judge will dismiss the action, or only allow the case to go forward based on a charge for which a prima facie case has been made. An example would be a murder trial where the state proved that the accused did in fact unlawfully strike the victim with a hammer but fails to show that the blow was a factor in the victim's death (or fails to show that the victim is, in fact, dead). In this scenario, the judge would dismiss the murder charge, but might allow the trial to proceed on the basis of a charge of assault and battery.

PRIVILEGE: Privilege refers to the rights of an accused person to refuse to testify against themselves, and to prevent the testimony of other specified person(s) with whom they have enjoyed a confidential relationship. The most common testimonial privileges, other than the Constitutional privilege against self-incrimination, are the husband/wife privilege, the attorney/client privilege, the priest/penitent privilege, and the physician/patient privilege. All these privileges do not exist in their entirety in every jurisdiction, and the physician/patient privilege does not exist as such in many jurisdictions. It should be noted that the privilege belongs to the client, the penitent, or the patient and does not belong to the professional. Thus, an Attorney cannot refuse to testify if his client does not wish to claim the privilege, an if an attorney were the accused in a criminal action, he could not assert the privilege to prevent his clients from testifying against him. Privilege should not be confused with immunity. The latter refers to whether a person can be punished for criminal acts. In the case of the privilege against self-incrimination, a grant of immunity from prosecution will eliminate the privilege. Thus, a person who has been granted immunity for certain criminal acts cannot refuse to testify about those acts.

RELEVANT: Evidence is relevant where it tends to prove or disprove a fact in issue in the lawsuit. It is a prerequisite to admissibility, but not the sole criterion.

RES IPSA LOQUITOR (“The thing speaks for itself.”): Method of proving negligence wherein the plaintiff shows that the instrumentality causing the injury was in the defendant's exclusive control, and that the accident was of a type that ordinarily does not occur in the absence of negligence. Such proof raises a presumption that the defendant was in fact negligent: however, the presumption is rebuttable, and the defendant is free to show that he did, in fact, exercise due care and was not guilty of negligence.

RESPONDEAT SUPERIOR: (“Let the master answer”) An employer is usually liable for the wrongful acts of an employee, so long as these acts arose from the course of the employment. Thus, a bus company is liable for the negligence of a bus driver who causes an accident while driving the bus; however, the company is not liable for the negligence of the employee if the employee has an accident while driving his own car on a Sunday afternoon. Similarly, a doctor is liable for the negligence of his nurse who carelessly injures a patient in the course of her employment.

STANDARD OF PROOF: Degree of proof necessary to prevail in a legal action. In civil actions, the side presenting proof by a “preponderance of the evidence” should prevail. In criminal actions, the government must present proof of guilt “beyond a reasonable doubt” in order to convict the accused. Thus, if “A” shoots “B” and ‘B” is sued for damages by “A” and “B” is also prosecuted for assault by the state, it is possible for “A” to prevail in his suit, but for “B” to be acquitted in the criminal trial. The reason might be that the degree of proof in the suit was by the ‘preponderance of the evidence” but did not reach “beyond a reasonable doubt.” (See Burden of Proof).

STIPULATION: An agreement by both parties to a suit. A stipulation may be a stipulation of fact, where the parties agree that a certain fact exists (“prosecution exhibit 1 contains heroin”); the existence of that fact is then binding in the case. A stipulation may be one of expected testimony, whereby the parties agree that if a certain witness were present, he would testify in a certain manner. Both parties would then treat the testimony as if it were given in open court. In this situation, the agreement does not extend to the truth of the facts asserted in the testimony, and the testimony of the absent witness may be disputed in any manner.

SUBPOENA: An order from a court of a competent jurisdiction that commands a person to appear before the court and testify.

SUBPOENA DUCES TECUM: An order from a court commanding a witness to appear and to bring with them items named in the subpoena.

TORT: A private or civil wrong independent of any contract. A tort involves a legal duty between plaintiff and defendant, a breach of the duty, and damages to the plaintiff as a result. A tort gives rise to a right in the plaintiff to recover damages from the defendant in a civil lawsuit.

The driver of an automobile has a general duty to the public to operate the car with due care for the safety of others; a breach of that duty involving injury to another is a tort.

A tort may or not be a crime, depending on whether the conduct comprising the tort has been prescribed by criminal laws or not. Thus, if an individual unlawfully shoots another, the act is a tort and a crime. The victim may or may not sue, as he elects. At the same time, the proper authorities may or may not decide to prosecute for criminal conduct. The first trial will be a civil suit between two private parties, as plaintiff and defendant; the second will be a criminal trial between the government and the defendant, wherein the victim will merely be a witness. Note that the decision as to whether to proceed with the two suits are made by different persons and are independent of one another. Further, the procedures both before and during trial may be quite different, as will the potential outcomes of the trials (monetary damages v. criminal penalty).

VENUE: A specific geographic area of the jurisdiction in which an injury is declared to have occurred and where the trial of the issue is held. In State cases, the venue would be the county within the state where the injury occurred. In criminal cases, the defendant may request that the place of the trial is changed due to adverse pre-trial publicity, or because the personalities involved are so well-known as to prevent a fair jury. In such a scenario, the defendant has asked for a change of venue.

VERDICT: The decision of a court or jury on questions submitted to them.

VICTIM: The expert should avoid the term “victim.” Alternatives include the person's name or the “decedent.”

VOIR DIRE: The preliminary examination that the court may execute concerning the competence or potential bias of a witness or juror.

AUTHORS

Susan F. Ely, MD, MPHTM, Office of Chief Medical Examiner, New York, NY, USA

Roles: A, C, D, E, 1

James R. Gill, MD, Office of the Chief Medical Examiner, Farmington, CT, USA

Roles: A, C, D, E