Bases of Forensic Pathology Expert Testimony With Emphasis on Iowa v Tyler

Abstract

Judicial scrutiny of the forensic sciences is increasing. This scrutiny targets the bases for expert opinions. Forensic pathologists must understand that when they express an opinion it must have an articulable underlying basis. Iowa v Tyler provides a cautionary tale where testimony from a forensic pathologist on the cause and manner of death based exclusively on police reports and audio and video recordings of police interviews of the suspect rather than on medical evidence were held to be inadmissible. Tyler has an odd and distinguishable set of facts, but has been widely cited as an example of problematic forensic pathology testimony.

Introduction

The practice of forensic pathology includes testifying in court as a professional expert. It is thus important that forensic pathologists understand the judicial scrutiny that they may face, particularly now that such scrutiny appears to be increasing. It should be recognized as a backdrop to this discussion that faulty forensic science testimony has contributed to wrongful convictions (1). Opposing counsel may challenge an expert: 1) directly through controverting testimony of other experts, 2) by impeaching the credibility of the witness, or 3) by attacking the underlying bases of the witness’s opinion. In this article, I will discuss legal requirements of expert testimony; I will not discuss the ethics (2) or the practical aspects of testifying (3 -5). I will particularly comment on Iowa v Tyler, which held that forensic pathologists cannot testify to opinions based solely on uncorroborated nonmedical data supplied by the police.

Expert Witnesses

Witness testimony is primarily governed by the Federal Rules of Evidence (FRE) (6). Although these federal rules apply only to federal courts, most, if not all, states have rules that are the same or similar.

Ordinary witnesses (also known as lay, fact, or percipient witnesses) testify to what they have directly observed through their senses—hence eyewitnesses, ear witnesses, and nose witnesses. FRE 701 limits ordinary witnesses to opinions which are rationally based on personal perceptions and not based upon scientific, technical, or other specialized knowledge.

In Anglo-American law, expert opinion testimony has been traced back to Folkes v Chadd (1781-1783) (a.k.a. the Wells Harbor case), in which the cause of the silting in of the harbor was at issue. Lord Chief Justice Mansfield wrote:

The whole question is a matter of opinion, from facts agreed upon.…It is objected to that Smeaton is going to speak, not as to facts, but as to opinion.…Mr. Smeaton understands the construction of harbors, the causes of their destruction, and how remedied. In matters of science no other witness can be called.…On certain matters, such as those of science or art, upon which the court itself cannot form an opinion, special study, skill or experience being required for the purpose, ‘expert’ witnesses may give evidence of their opinion (7 -9).

The FRE 702 provides the current framework for expert witness testimony:

Rule 702—Testimony by Expert Witnesses

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

1. the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;

2. the testimony is based on sufficient facts or data;

3. the testimony is the product of reliable principles and methods; and

4. the expert has reliably applied the principles and methods to the facts of the case.

This rule emphasizes that expert witnesses have specialized knowledge beyond the ken of laymen. This specialized knowledge can be scientific, technical, or other. The expert is qualified by knowledge, skill, experience, training, or education that the average citizen does not possess. The attorney proffering the expert must lay a foundation, which should include the witness’s educational and work experience that qualifies the expert. The judge must recognize that the witness is qualified as competent to testify as an expert. Once qualified, the expert can testify to his or her opinion, but only if certain other conditions apply, including that the opinion be helpful to the trier of fact (the jury or the judge in a bench trial), and is not inflammatory or should be excluded for some other reason (FRE 403).

Forensic pathologists testify as expert witnesses. The education and training of forensic pathologists is substantial. Autopsies are performed only by licensed physicians and completely beyond the experience of the average citizen. Lay persons are not permitted to testify that a death was due to a gunshot wound to the head as obvious as that may be, because not all gunshot wounds to the head are fatal. To merely describe a slice of liver is beyond the ken of lay persons, because they do not know what would constitute an abnormal color or firmness. The autopsy report is full of jargon that must be explained to jurors. Forensic pathologists are occasionally called to testify as ordinary fact witnesses, but they should not.

Bases of Opinion

FRE 702 requires that the testimony be: 1) based on sufficient facts or data, 2) the product of reliable principles and methods, and 3) those principles and methods reliably applied to the facts of the case. FRE 702 is followed by:

Rule 703—Bases of an An expert may base an opinion on facts or data in the case that the expert has been made aware of or personally observed. If experts in the particular field would reasonably rely on those kinds of facts or data in forming an opinion on the subject, they need not be admissible for the opinion to be admitted. But if the facts or data would otherwise be inadmissible, the proponent of the opinion may disclose them to the jury only if their probative value in helping the jury evaluate the opinion substantially outweighs their prejudicial effect.

Rule 705—Disclosing the Facts or Data Underlying an Expert

Unless the court orders otherwise, an expert may state an opinion—and give the reasons for it—without first testifying to the underlying facts or data. But the expert may be required to disclose those facts or data on cross-examination.

FRE 703 states that the bases for the opinion must be from facts or data that the expert has either: 1) personally observed or 2) been made aware of (10). Those facts or data need not be admissible and FRE 705 states that the expert witness does not have to disclose the facts or data that forms the basis for the opinion to the jury unless forced by the opposing counsel.

Although the bases for the expert opinion are not necessarily disclosed to the jury, nonetheless the bases will generally be disclosed to the opposing party. In the case of criminal trials, under the Federal Rules of Criminal Procedure Rule 16(G) at the defendant’s request, the prosecution must provide a written summary of testimony, which must describe the witness’s opinions, the bases and reasons for those opinions, and the witness’s qualifications. In the case of civil trials, Federal Rule of Civil Procedure Rule 26(B) requires that written reports of expert witnesses must contain, among other things, “1) a complete statement of all opinions the witness will express and the basis and reasons for them; 2) the facts or data considered by the witness in forming them.” Again, these are federal rules, but states have generally adopted some version of them.

Burden of Proof

The proponent of the expert has the burden of establishing the admissibility of an expert’s testimony. Expert witnesses generally opine to a preponderance of the evidence. Even in criminal trials, when witnesses are asked to give their opinion and it need not be beyond reasonable doubt. The opinion must be more than a hunch or reasonable suspicion, it must be a statement of belief that something is more likely to be true than not. If, in the professional opinion of the forensic pathologist, something is less than probable, then it should not be expressed as an opinion on the witness stand and the witness may have to answer that he or she does not have an opinion.

Attorneys have become accustomed to ask if the expert’s opinion is to a reasonable medical certainty or to a reasonable scientific certainty, a higher standard than a mere preponderance. In some jurisdictions, it is really only a habit, but in other jurisdictions use of these magic words have become a legal requirement by way of caselaw. The National Commission on Forensic Sciences recommended that the term be dropped (11) and the U.S. Attorney General issued a memo to U.S. Attorneys and Assistant U.S. Attorneys that they not use the term where possible (12).

Reliable Science

Perhaps arguably, the first major case to rule on the admissibility of scientific evidence was the U.S. v Frye (1923) which involved a new systolic blood pressure deception test (an early form of lie detector test) (13). The D.C. Court of Appeals held that to be admitted into evidence, novel science had to be generally accepted by experts in the particular field in which it belongs. Previously, all scientific evidence was admitted to the jury to weigh, but Frye introduced admissibility step—that, as a matter of law, the judge could preclude the jury from hearing the testimony. States quickly adopted the new rule.

In Daubert v Merrill Dow Pharmaceuticals, Inc. (1993), U.S. Supreme Court ruled that the FRE had superseded the Frye rule (14). The FRE have a liberal thrust, intentionally tending to admit evidence to the jury, and thus was seen as more accepting of scientific evidence than Frye. The Court shifted the determination of acceptability from the scientific community opinion to the judge as the gatekeeper of evidentiary admissibility. The Court established a list of factors to consider if the scientific evidence is sufficiently reliable to admit to the factfinder: 1) whether the theory or technique in question can be and has been tested, 2) whether it has been subjected to peer review and publication, 3) whether the error rate is known, 4) whether standards controlling its operation exist, and 5) whether it has attracted general acceptance within a relevant scientific community. The Court made clear that these Daubert factors were supposed to be nonexclusive guidance, but many courts have taken them as literal requirements.

Most states have adopted the federal Daubert standard, but a few have retained the Frye rule and a handful have fashioned their own version (15). Under the Frye rule, once a novel scientific method has been ruled as generally accepted then it will be considered to be accepted within that jurisdiction; but under the Daubert standard, the science may be challenged anew with each new case.

In Kumho Tire Co. v Carmichael (1999), the U.S. Supreme Court held that the Daubert considerations apply to nonscientific specialized knowledge, including technical knowledge and experience (16).

As Daubert makes clear (14), the judge is the gatekeeper who rules on the competency of the expert witness and the admissibility of the scientific evidence based upon the FRE:

Rule 104(a) In General

The court must decide any preliminary question about whether a witness is qualified, a privilege exists, or evidence is admissible. In so deciding, the court is not bound by evidence rules, except those on privilege.

Typically, the science is challenged in a pretrial motion in limine requesting that certain inadmissible evidence not be referred to or offered at trial that may result in a Daubert, Frye, or similar hearing to assess the reliability of the scientific evidence. Occasionally such hearings will be interlocutory (during the trial proceedings). GE v Joiner (1997) made clear that the standard for appeal for decisions on the admissibility of expert testimony is abuse of discretion (17).

Reliance on Nonmedical Information

Testimony of experts is attacked through challenges to 1) the expertise of the expert, 2) the expert’s opinion, or 3) the bases of the expert’s opinion. Such attacks can undermine the credibility of the witness or result in the testimony being held inadmissible. Opposing counsel may claim that the opinion of the expert lacks a scientific background. Counsel may claim that the opinion is a subjective interpretation of the facts and not based upon objective facts. Counsel may emphasize the uncertainty of the opinion or that it is subject to bias. Ultimately, the proffered testimony must be found to be helpful to the jury rather than misleading the jury. In the case of the forensic pathologist, the greater the reliance on nonmedical facts, the less expertise appears to be involved, the more subjective the opinion seems, and the more exposed the expert is to such attacks.

Medicolegal death investigation systems are charged with the duty to investigate certain cases of deaths. Typically, medicolegal death investigation authorities attempt to obtain the police reports, emergency medical reports, and hospital records, among other relevant information. Forensic pathologists must have some understanding of the known background and circumstances of the deaths as they perform postmortem examinations and autopsies. Conversely, the forensic pathologist should compare the history to the findings, and when they don’t agree, then the history should be suspect. To these physicians, the background and circumstances of the death are the medical history and the postmortem examination and autopsy are the physical exam. In determining the cause and manner of death, medical examiners and coroners are all source decision-makers. From the standpoint of FRE 703, the postmortem examination and autopsy permits personal observation, and the known background and circumstances of the death are the facts or data in the case that experts in the field reasonably rely on to render their professional expert opinions on the cause and manner of death.

Iowa v. Tyler

In Tyler v. Iowa (IA 2014) (18), the testimony of a forensic pathologist was held by the Iowa Supreme Court to be inadmissible evidence, where the forensic pathologist relied exclusively on information supplied by the police that contained uncorroborated statements of the defendant to determine the cause and manner of death of an infant death. Tyler has been widely cited as an example of problematic forensic pathology testimony, but it should be seen as exceptional.

Investigative background

Hillary Tyler delivered “Baby Tyler” alone in a rented hotel room. The hotel staff found blood in the room before Tyler was able to return and clean up; the hotel manager called the police. The police found the baby’s body in the waste basket. Detectives in plain clothes went to the trailer house where Hillary Tyler lived. She answered a few questions and agreed to go to the police station. Without giving her Miranda rights and informing her that she was not in custody and free to leave, she was questioned in the car on the way to the station and then for 3 hours at the station. She was also repeatedly asked if she needed medical attention. Initially, during the first 45 minutes of the interrogation in response to open-ended questions, she maintained that the baby was born silent, did not move, and was immediately placed in the waste basket. After a 45-minute break, a pointed interrogation began. Eventually, Tyler stated that after the delivery, the baby cried and moved, and then she placed him in the bathtub and turned on the water to drown him. After another short break, she was informed that she would be charged and was read her Miranda rights. Tyler confirmed the new story. The next day, she went to the hospital, where she was treated for preeclampsia and blood loss and received a surgical repair for a tear from childbirth. The following day, while still in the hospital, she was asked again about what happened and again reiterated that she had placed the baby in the bathtub and turned on the water to drown him.

Tyler later claimed in her pleadings that her statements to the police were coerced and not credible. She admitted to the baby drowning only after 45 minutes of police interrogation and a 43-minute break and at a time when she was in need of medical care. She further claimed that her admission in the hospital was while she was medicated and in a vulnerable state.

Autopsy

An Associate State Medical Examiner performed a complete autopsy on the body, the placenta, and a portion of the umbilical cord. The autopsy included a microscopic examination and laboratory tests. He also read the police reports and viewed both the video of the interview at the police station and listened to the audio recording of the follow-up interview at the hospital. His preliminary opinion was “undetermined” cause and manner of death, but in his final report he concluded the cause of death was “Bathtub drowning” and the manner of death was “Homicide.” In his autopsy report, he stated that in forming his opinions he relied on Tyler’s statements to police.

Pretrial motions

In addition to objections to the statements made and evidence gathered, the defense made a motion in limine during a pretrial hearing to exclude the forensic pathologist’s testimony as it was not based on any scientific or medical knowledge. The forensic pathologist was questioned during this hearing:

Q. In this case, if you based your opinions speaking strictly on medical or scientific evidence, you were unable to give a conclusion as to whether or not this was a homicide, correct? A. Just on the autopsy findings, that would be correct, yes.

Q. Okay. And also based just on the autopsy findings, you would be unable to determine whether or not this was a drowning, correct? A. That would be correct, yes.

Q. The autopsy findings were consistent with intrauterine fetal demise, correct? A. They could be, yes.

Q. They could also be consistent with a baby that died immediately after birth, correct? A. It could be, yes.

….

Q. Okay. So the specific autopsy, the testing that you did, the toxicology test, the examination of the lungs, all of the things you did, the examination of the stomach contents, all of that led you to an inconclusive determination, correct? A. That’s correct, yes.

Q. And the only way that you reached the conclusion of homicide as the manner of death, as drowning as a cause of death, is through observing and watching the videotapes that the law enforcement officers supplied to you, correct? A. Yes, it is.

Q. So that would be of Miss Tyler’s interview with the police, correct? A. That’s correct.

….

Q. Okay. So from that standpoint, ultimately your opinion as to whether or not this was a homicide…and what the cause of death was, is based entirely on your belief of her statements, correct? A. That’s correct, yes.

….

Q. Okay.…[E]ssentially what you’re saying is that since the autopsy didn’t disprove her statement, you’re going to believe her statement? A. That’s correct, yes. There’s nothing inconsistent between what she said and what I saw at the autopsy (18).

The trial judge overruled Tyler’s pretrial objection to the forensic pathologist’s testimony citing Iowa’s liberal policy toward the admission of expert testimony and noting that the forensic pathologist’ reliance on the police statements was no different than his reliance on patient histories to reach diagnoses.

Trial

The central issue at trial was whether Baby Tyler was born stillborn, died immediately after birth, or was drowned.

The forensic pathologist testified he found fluid in Baby Tyler’s lungs. However, this fluid was, at least in part, amniotic fluid, and he stated that he could not determine whether some of the fluid was bathwater. He further testified that there were indications that Baby Tyler had taken a breath because the alveoli in the lungs were partially, although not entirely, expanded; further, the history that Baby Tyler cried and moved also was evidence that Baby Tyler was breathing. The forensic pathologist testified that based on his findings, he was able to rule out several possible alternative causes of death. He then opined that the cause of death was drowning, and the manner was homicide. Finally, the forensic pathologist testified that his opinions were based on “a combination of history, which includes scene findings, it includes witness statements; it’s also based on a combination of physical exam, which is [the] autopsy findings; and then supplemental testing (18).”

On cross-examination, the defense called attention to the inconclusive nature of the autopsy findings. When the defense asked if there was an alternative explanation for the partially expanded alveoli in the lungs, the forensic pathologist explained that partially expanded alveoli would also be consistent with postmortem gas production. When the defense asked whether it was possible, based on the autopsy, that Baby Tyler was stillborn or died immediately after birth, the forensic pathologist replied that there were several other possible causes of death he could not rule out based on the autopsy findings alone. He agreed with the defense that it was possible Baby Tyler died either in utero or immediately after birth. The following exchange occurred on the cause and manner of death:

Q. Okay. It is true that you cannot say from your autopsy alone that the child in this case ever took a breath, correct? A. That’s correct, yes.

Q…. For that opinion, you are entirely relying on the review of the interview in this case; is that correct? A. Uh, not necessarily, because there’s nothing inconsistent with what the witness statement said with the autopsy findings.

Q. Well—A. But without the witness statements, I could not have diagnosed drowning in this case.

Q. You had conducted your autopsy, correct? A. Yes.

Q. Your opinion was undetermined at that time? A. That’s correct, yes.

Q. And then the only way you came up with your decision in this case was based on the interview you watched? A. Yes, sir, that’s correct.

Q. Now, you’re relying on the fact that [Tyler] said prior to putting the baby in the tub, the baby moved and cried, correct? A. Yes, sir (18).

Tyler presented her own pathologist expert, who testified that there was insufficient information to determine the cause or manner of death.

The jury found Tyler guilty of the lesser included offense of murder in the second degree.

Appeal

Tyler appealed her conviction, among other things claiming that the trial court erred when it allowed the forensic pathologist to testify on the cause and manner of Baby Tyler’s death over her objection. The court of appeals ruled that the trial court abused its discretion in allowing the forensic pathologist to testify to the cause and manner of death and in admitting the unredacted autopsy report into evidence and the Iowa Supreme Court later affirmed. The state supreme court held that there were four reasons to exclude the testimony: 1) the forensic pathologist’s opinion was not based on objective, scientific, or medical evidence; 2) the testimony was not helpful to the jury; 3) the testimony amounted to an impermissible comment on the credibility of the statements of the defendant; and 4) the court doubted that the testimony rose to the level of reasonable medical certainty. The court concluded that the admission of his testimony was reversible error because it was the central issue in the case and remanded the case for a new trial excluding the forensic pathologist’s testimony as to the cause and manner of death.

The state supreme court found the state medical examiner’s opinions on the cause and manner of death were inadmissible because they could not fairly be characterized as expert medical opinions, instead the court found his opinions to be based primarily, if not exclusively, on Tyler’s inconsistent and uncorroborated statements to the police, as opposed to objective, scientific, or medical evidence.

Without the benefit of objective medical findings, [the forensic pathologist] testified to the ultimate issues of fact questions for the jury to determine (18).

The court pointed to: 1) his changing of his opinion from undetermined to homicidal drowning, 2) his pretrial hearing testimony, and 3) his trial testimony—all of which showed that Tyler’s incriminating statements and not the autopsy were the basis for his opinions.

[The forensic pathologist] admitted that his opinions on the cause and manner of Baby Tyler’s death were based primarily, if not exclusively, on Tyler’s inconsistent and uncorroborated statements to police, as opposed to objective medical findings (18).

This is not a case where the medical examiner simply considered witness statements or information obtained from police, but based his or her opinions primarily on the physical evidence (18).

[T]he record does not support the conclusion that [the forensic pathologist] relied on any other corroborating evidence, aside from Tyler’s statements (18).

[The forensic pathologist] did testify that his opinions were based on ‘a combination of history, which includes scene findings [and] witness statements,’ in addition to ‘[the] autopsy findings…and…supplemental testing.’ However, he did not explain how the scene findings or other objective information factored into his opinions. In fact, the record is devoid of any such objective evidence. Instead, he admitted Tyler’s statements to police were the but-for factor in rendering his opinion. Consequently, [the medical examiner’s] opinions on the cause and manner of death were not sufficiently based on scientific, technical, or other specialized knowledge as required by our rules (18).

The court reviewed the legal literature for precedent in the area. The court cited seven cases in which courts held forensic pathology relying on police reports were inadmissible and nine cases in which the testimony was allowed. The court quoted the concurrence in Baraka v Commonwealth (Ky. 2006):

The consensus of these cases is that an expert medical examiner or forensic pathologist can express an opinion not only as to the cause of death, but also that the manner of death was homicide…where such would not be readily ascertainable by a layperson, thus would assist that trier of fact in determining a fact in issue. However, the expert cannot express an opinion as to the mental state of the accused which would constitute an expression as to guilt or innocence, and cannot base the opinion solely on facts that are just as easily understood by a layperson (18).

The Iowa supreme court ultimately concluded:

our review of the caselaw confirms there is no bright-line rule for determining whether a medical examiner may opine on cause or manner of death when his or her opinions are based, in whole or in part, on such information. Instead, whether a medical examiner’s opinion on cause or manner of death is admissible depends on the particular circumstances of each case (18).

First, the court held that the testimony was inadmissible because it was not helpful to the jury; it was not sufficiently “specialized knowledge” and was redundant of facts already in evidence.

We note that this case does not present an issue of whether an expert witness may rely on facts or data not in evidence…Here, the facts and data relied on by [the forensic pathologist] were ultimately admitted into evidence (18).

Clearly, a medical examiner could testify concerning the medical signs of drowning, whether the autopsy findings were consistent with drowning, whether there were other possible causes of death, whether he or she could rule out other possible causes of death, and whether he or she could legitimately render definitive opinions on cause or manner of death. Much of [the forensic pathologist’s] testimony assisted the jury in these respects. However, the record in this case does not support the conclusion that [the forensic pathologist] relied on scientific, technical, or other specialized knowledge to classify the cause of Baby Tyler’s death as bathtub drowning or the manner of his death as homicide, rather than undetermined (18).

Second, the court held that the opinions of the forensic pathologist were inadmissible because they amounted to an impermissible comment on Tyler’s credibility (18). An expert cannot comment, directly or indirectly, on a witness’s credibility, because it is not a “fact in issue” and to do so invades the province of the jury. Here the reliance on Tyler’s statements implies that they are thought to be true—essentially vouches for the credibility of the defendant.

Third, the court had serious doubts as to whether the forensic pathologist possessed a reasonable degree of medical certainty with respect to his opinions on the cause and manner of death (18).

In the view of the author, the forensic pathologist should not have relied exclusively on Tyler’s statements. The autopsy is a powerful tool and it should have some value in the determination of the manner of death. The forensic pathologist might have performed a float test of the lungs, using a piece of liver as a control for postmortem gas production. Squames in the alveolar spaces might have suggested amniotic fluid aspiration and their absence may have suggested otherwise. Drownings probably produce heavier lungs than cases with amniotic fluid aspiration. Water in the sinuses and watery gastric content might be more in keeping with drowning. Even if none of these is definitive, they may be suggestive, particularly as a collective. Of course, a negative autopsy itself can be useful to rule out other potential causes. Beyond the autopsy, there were other known circumstances of the death other than the defendant statements that would seem to bear on the determination of the manner of death. Regardless, such total dependence on police reports as testified to by the forensic pathologist is distinctly uncommon and the case should not stand for a general rule; in fact, the Iowa supreme court itself described the facts of the case as “unique” (18).

Adams v. Iowa

In the subsequent case of Adams v. Iowa (19), the defendant sought exclusion of a forensic pathologist’s testimony on cause and manner of death “because 1) the testimony was unreliable and had little scientific basis, and 2) based entirely upon information provided by law enforcement.” The forensic pathologist in Adams testified differently than in Tyler which yielded a different outcome.

The court dismissed a claim, referencing Tyler, that the medical examiner’s opinion was heavily reliant on information from law enforcement because it was raised for the first time upon appeal. Nonetheless, the court considered the admissibility of the expert testimony focusing on its medical and scientific underpinning.

The forensic pathologist opined that the child died of homicidal suffocation based upon watching a videotaped doll reenactment in which Adam’s held the child face down on a pillow. The forensic pathologist described how he made his determination:

It is a combination of processes.…there is no definitive finding per se for suffocation…look at the circumstances…also a process of eliminating all other known reasonable cause[s] of death…did a complete thorough autopsy and ran numerous tests to rule out all those other causes…and you correlate that with what we’re told and the circumstances surrounding the death.

At one point, the defense counsel pressed the forensic pathologist for a source for his opinion that the force to hold down the head wouldn’t necessarily leave a bruise or other physical finding. The forensic pathologist could not cite a specific scientific study nor assert a generally-accepted opinion on the subject. The defense then objected that the opinion lacked a scientific basis. The court acknowledged that it would be impossible to conduct controlled scientific studies on the issue because it would involve the intentional infliction of serious injuries on human subjects. Accordingly, the court rejected the objection.

The court upheld the admission of the testimony and noted that the forensic pathologist

reached his conclusion based upon the autopsy, his knowledge and expertise, the video reenactment, and information from law enforcement…the medical examiner noted objective findings supporting his conclusions [bruising behind the child’s ear]

Nonmedical Background Information

Simon has asserted that medicolegal death investigation is not entirely driven by objective scientific findings and has suggested that the “background information” used by forensic pathologists’ may explicitly bias determinations of cause and manner of death (20). He acknowledges that

In their capacity as death certifiers, forensic pathologists serve effectively as ultimate decision makers. They also operate as ‘all-source experts,’ in that they evaluate all the evidence—of both medical and nonmedical kinds—and draw their best judgment from that evidence.

He categorizes this background information in “descending order of proximity to the scientific core” as: 1) medical history, 2) findings from death scenes, 3) social history, and 4) information from police investigation.

Simon declares that the medicolegal death investigation task should be understood as “requiring a far more complex, sprawling, iterative, and open-ended form of reasoning.” He describes the abductive reasoning process of forensic pathologists in which hypotheses are generated, tested, and evaluated to derive the optimal explanation for the death. He poses a hypothetical example to demonstrate: “The crux of the issue is that the autopsy findings readily fit a number of different explanations, each of which will hinge—to a large extent or exclusively—on background information.” He recognizes that forensic pathologists must accomplish this within short time spans.

Simon acknowledges the iterative nature of the process, yet he seems to fail to appreciate the substantial interplay between the background information and the autopsy. The autopsy is used to confirm the history and the history is used to confirm the autopsy findings. The autopsy examination is targeted to the history and more investigation is often required from the autopsy findings. Thus, the distinction between the background information and the objective scientific findings become blurred. Adams seems to exemplify this point.

Simon proposes that context management, using a linear sequential unmasking approach, in which social history and information from police be temporarily masked in “a small category of ambiguous criminal cases.” He acknowledges that this process may deprive the forensic pathologist of important diagnostic information, prevent some hypothesis generation, and require significant resources to implement. Thus, he recognizes that his proposal will promote accuracy in some cases and thwart accuracy in other cases and that often medical examiners will not be able to distinguish these two results. Furthermore, he recognizes that this would burden the workload in all death investigations.

Simon assumes that medicolegal death investigations go awry and go awry due to exposure of misleading information. The only example that Simon points to is Tyler. Most forensic pathologists recognize that histories can be wrong and are suspicious of histories; however, they also firmly believe that histories are necessary and are strongly opposed to any context masking schemes.

Manner of Death Testimony

Although not an issue in the case, some attorneys have pointed to Iowa v. Tyler for the proposition that forensic pathologists should not testify to the manner of death. This is because the manner of death, more than the cause of death, is so dependent on the circumstances reported to the forensic pathologist. In fact, the court noted that the Iowa administrative code defines “Manner of death” as “the circumstances under which the cause of death occurred (21),” but this is a poor and incomplete definition. The manner of death is best regarded as a public health nosologic classification for use in the National Vital Statistics System upon which the circumstances bear prominently, but not exclusively, on its determination.

Medical examiners have a statutory duty to investigate deaths and determine the cause and manner of death. Like the determination of the cause of death, the determination of the manner of death is an all-source decision and should rely on those sources that are needed, which may include the autopsy. As recognized in the statute, medical examiners are in a special position to best make the determination of manner of death. Forensic pathologists are well aware of patterns that suggest suicide that are not necessarily apparent to others who do not have experience with them. In fact, forensic pathologists have significant experience in certifying deaths and have developed a literature on manner of death determinations. However, the premise for such authority is that medical examiners are using their medical knowledge to make such determinations.

Another concern regarding manner testimony is the notion that it goes to the “ultimate question.” FRE 704 declares that an opinion is not automatically objectionable because it embraces an ultimate issue (unless it goes to the mental state of the defendant), but not all states follow FRE 704 and allow testimony to the ultimate question. However, to testify that a death is a homicide is to testify to an element of the crime divorced from any thought of criminal responsibility. Moreover, homicide to the forensic pathologist is not a legal conclusion, but rather an opinion expressed on the death certificate of a nosologic conclusion. Generally, the legal test of the admissibility of an opinion on the ultimate question will be whether the opinion is rationally-based and will be helpful to the trier of fact (22). Thus, in the opinion of the author, the forensic pathologist’s determination should be admissible as a fact in evidence.

Conclusion

Forensic pathologists should expect that the basis for their opinions will be attacked and should have sound bases for their opinions that do not solely rely on uncorroborated witness statements or other nonmedical information.

AUTHOR

Victor W. Weedn, MD, JD, Maryland Office of the Chief Medical Examiner

Roles: A, B, C, D, E, 1, 4, 6