enced forensic odontologist.1 Human bite marks can be found on the skin of the living or deceased, adult or child, victim or suspect. They can also be found on. The aim of this paper is to give a brief overview of bite mark analysis: its usefulness and limitations. The study and analysis of such injuries is. The analysis of human bite marks is by far the most challenging and detailed part of forensic Keywords: assailant, sexual abuse, bite marks, forensic dentistry.
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Several forensic sciences, especially of the pattern-matching kind, are increasingly seen to lack the scientific foundation needed to justify continuing admission as trial evidence.
Indeed, several have been abolished in the recent past. A likely next candidate for elimination is bitemark identification. A number of DNA exonerations have occurred in recent years for individuals convicted based on erroneous bitemark identifications. Intense scientific and legal odontklogy has resulted. An important National Academies review found little scientific support for the field.
The Texas Forensic Science Commission recently recommended a moratorium on the admission of bitemark expert testimony. The California Supreme Court has a case before it that could start a national dismantling of forensic odontology. This article describes the legal basis for the rise of bitemark identification and the scientific basis for its impending fall.
The article explains the general logic of forensic identification, the claims of bitemark identification, and reviews relevant empirical research on bitemark identification—highlighting both the lack of research and the lack of support provided by what research does exist.
The rise and possible fall of bitemark identification evidence has broader implications—highlighting the weak scientific culture of forensic science and the law’s difficulty in evaluating and responding to unreliable and unscientific evidence. Forensic evidence used in criminal cases has never experienced greater legal and scientific scrutiny than it does today. Some types of forensic science expert testimony, particularly some of the pattern-matching subfields, have in recent years come to be recognized as standing on foundations so weak and making claims so exaggerated that the justification for admitting them as evidence in court has been called into serious doubt.
Some of those types of forensic testimony had been used for decades without any judicial concerns being raised. Studies of wrongful convictions based on DNA exonerations have found the forensic sciences to be second only to eyewitness errors as a source of false or misleading evidence contributing to erroneous convictions.
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The eulogy for voiceprints was given by the National Academy of Sciences in5 following which the FBI ceased offering such experts in support of any prosecution case in chief, and the discipline slid into decline. More recently, comparative bullet lead analysis met the same fate. The most likely candidate to next join those fields and techniques in the cemetery of terminated forensic sciences is forensic odontology—the comparison of suspected bite marks usually found in the flesh of crime victims and the dentition of suspects.
The claim of forensic dentists has been that they can accurately associate a bite mark to the one and only set of teeth in the world that could have produced the crime scene bite bute. However, as this article will explain, no sound basis exists for believing that forensic dentists can perform such a feat.
Despite the lack of empirical evidence to support its claims, to date no court in the United States has excluded such expert evidence for failing to meet the requisite legal standard for admission of expert testimony.
Only in rare instances did judges even raise questions concerning the trustworthiness of such evidence, even after errors in btie identifications came to light. In a series of high-profile cases, including DNA exonerations, bitemark identifications have been exposed as erroneous. Had the California Supreme Court decided a recent case more broadly than it did–holding as it did not that such evidence generally lacks reliability and validity—it might have started a cascade of similar exclusions in other jurisdictions.
Forehsic section immediately below reviews the legal basis for admissibility of opinion testimony on identification by means of bite marks. Our focus then turns to the scientific deficiencies of bitemark expert evidence. The next section discusses the growing recognition of doubts about the odotnology of forensic odontology.
The section following that explains the general logic of forensic identification. The section after that discusses the claims of bitemark identification against that background of general principles.
The last major section focuses on studies assessing the accuracy of bitemark identification. Finally, we conclude by examining what the life cycle of the field of bitemark identification portends for forensic disciplines more broadly, and what lessons can be drawn for both the scientific and legal communities.
Forensic scientists, researchers, lawyers, judges, and policymakers must all now grapple with the legacy of decades of unreliable forensics used in our courtrooms. In addition to auditing the misuse of science in the past, difficult challenges remain to ensure that judges adequately screen scientific evidence in criminal cases in the future.
The story of the rise and fall of bitemark identification suggests the perils of path dependency nite judicial review of scientific evidence and the terrible miscarriages of justice that can result when judges uncritically admit unvalidated expert accept into evidence. The lessons currently being learned will need to be remembered in the i to come. Beforeforensic dentists confined themselves to trying to identify victims of natural or human-caused disasters.
Frequently, those situations provided odontologists with the complete dentition of a small, well-defined set of individuals, who needed to be distinguished from each other. Untilthe discipline refrained from trying to identify the source of a bite mark left in skin because the differences between identifying victims of mass disasters and identifying the source of a crime scene bite mark seemed to them prohibitively daunting:.
The two tasks differ in important ways. In the disaster situation, there is a finite number of candidates to identify, and full dentition often is available from the victims as well as from the dental charts. In forensic bitemark cases, the number of potential suspects is huge, the bitemarks include only a limited portion of the dentition, and flesh is a far less clear medium than having the teeth of the disaster victim themselves.
Thus, crime scene bite marks contain only a small fraction of the information available from the full dentition of mass disaster victims, and the limited dental information that is available is neither clear flesh is far from an ideal medium for recording bite marks nor dependably accurate flesh is elastic and subject odohtology distortion at the time of and after receiving the bite.
The California case of People v.
Forensic dentistry – Wikipedia
Marx 14 presented what three forensic dentists, led by Gerry Vale of the Odonotlogy School of Dentistry, thought was a justifiable exception to the rule among forensic dentists that crime scene bite marks could not be trusted to yield accurate source identifications. The Marx case involved a murder victim with an elliptical laceration on her nose.
The laceration was judged to be a human bite; impressions were made of the wound and compared to a cast of the defendant’s teeth. At trial, the three dentists testified that in their opinion the observable portion of the unknown teeth that made the wound were indistinguishably similar to the comparable teeth of the defendant.
Vale took pains to note that odnotology many other cases they had refused to opine on the source of crime scene bite marks for the reasons described in the preceding paragraph. This case, they felt, was a rare exception to the general rule. Maeks teeth that made the bite mark were highly unusual and the bite mark was exceptionally well defined and three dimensional because nasal skin is stretched taughtly over underlying bone and cartilage, nasal tissue is firmer than the tissue of other body parts where bite marks are found, such as breasts.
The witnesses characterized these bite impressions as the clearest they had ever seen, either personally or in the literature. The defense challenged the admissibility of the expert testimony in Marx on two major grounds. First, that it was novel and not generally accepted by the field of odontology and therefore was inadmissible under California’s Kelly-Frye test.
Second, that it violated the doctrine of another California case, People mrks. The bitemark expert evidence was admitted at trial and the resulting conviction was appealed. The court of appeals turned away the first ground of attack by interpreting a technique’s novelty to refer not to the novelty of the identification theory being employed, but to the tools employed to visualize the bite mark and the suspect’s dentition.
Moreover, the court thought that Kelly-Frye was inapplicable in Marxreasoning that such a test applied only to evidence that was indecipherable without an expert’s interpretation, whereas Marx involved models, X-rays, and slides of the victim’s wounds and the accused’s dentition, all of which were clearly visible for the jurors to view, assess, and verify on their own during court proceedings, without having to rely on the expert odontologist as a necessary intermediary.
The most sensible, and charitable, reading of Marx would mars that the court understood, along with the forensic dentists, that the circumstances of the injury presented an unusually stable bite mark of an apparently very unusual set of teeth. In short, the offer and the admission in Marx constituted a rare exception to the general rule among forensic dentists that ldontology marks were bitw poor basis for trying to compare patterns.
Marx became the paradoxical seed from which most, if not all, subsequent decisions about admissibility of mars expert testimony grew. Marx came to stand for the very proposition that the experts in the case, and their field, had up to that point explicitly, collectively rejected. What had been an exception to the rule magically became the rule, not only for courts but for forensic dentists as well.
But, ironically, rather than forensic dentists convincing courts that their field could accurately identify the sources of bite marks, the courts convinced forensic dentists that they could do what until then they doubted they bote do.
Forensic bitemark identification: weak foundations, exaggerated claims
The following year, Illinois considered for the first time the issue of admissibility of bitemark evidence. Relying in part on Marxin People v. The marke of three forensic dentists was offered by the prosecution and four by the defense. The defense experts testified and cited odontological literature showing, at the least, an absence of any consensus among forensic dentists as to whether perpetrators could be bitee from bites left in the flesh of victims.
Notwithstanding the controversy in the trial record and in the literature, the court found that the general acceptance standard had been met. Bymmarks California Court of Appeals flatly held that the testimony of three forensic odontologists established that bitemark identification had attained the required general acceptance in the odonology scientific community. Daubertdespite its requirement for establishing scientific validity as a condition of admissibility, appears to have changed nothing.
The two earliest post- Daubert cases, in federal courts, decided more than a decade after Daubert illustrate the difficulty courts have in focusing on the validity of the asserted forensic expertise.
Town of Forsnsic24 the plaintiff alleged civil right violations against Massachusetts for his wrongful arrest and imprisonment, based heavily on a bitemark examination which purported to identify him as the person whose bite mark was found on the body of a murder victim.
He was later exonerated by DNA typing. In the course of drafting recommended findings concerning the Commonwealth’s motion to dismiss, the federal magistrate judge appeared never to doubt the validity of bitemark expertise though the best the court could do to support its faith was to cite cases that cite cases that express the same credulousness. The defendant had been ib of murder 9 years after the underlying crime took place and served more than 10 years of a life sentence by the time the federal court granted relief.
At the original trial, the defendant had been convicted in large part on the testimony of a forensic dentist whose opinion it was that a mark on the cheek of the victim, visible in a photograph of the corpse, was a human bite mark and that the mark matched the dentition of the defendant and no one other than the defendant. The odontologist stated that out of the 3. The petitioner argued that the bitemark testimony had been improperly admitted because it lacked any scientific foundation and that the statistical probability given had an exaggerated impact on the jury.
But the court’s condemnation of the bitemark testimony did not go to fundamental weaknesses of bitemark comparison; it was instead aimed at case-specific, even witness-specific, problems. One ground for the court’s concern was that the comparison was made using a photograph of the wound. What was problematic about this the court does not say.
The habeas court does not say what was wrong with Dr. Warnick’s examinations, or if they were standard practice among forensic dentists. The final flaw found by the court was that Dr. Warnick expressed his opinion through an explicit probability value. The court goes on at some length, discussing and citing numerous cases that raise doubts about inferences based on probability estimates. What the court failed to appreciate is that all of forensic odontology relies on these same notions to reach their conclusions of identity.
Warnick expressed his conclusion by uttering a number while his brethren typically do so by asserting verbally that dentition is unique among all humans, that the defendant’s dentition matches the bite mark, and therefore the defendant has to be the source of the bite mark markz the exclusion of all other possible sources.
Marsk number was less extreme and no more scientifically unjustified than the verbal formulation typically presented by forensic dentists. The court seems unaware of that. Egelike Burkeassumes the general soundness of the methods of bitemark comparison, but finds fault with the particular individual performing the comparisons.
By attacking this particular witness and his particular testimony with such vigor, the court avoided placing the field’s more general shortcomings under scrutiny. The problem with the expert witness seems not to be that he deviated from his discipline’s generally accepted practices so much as that he followed them.
As of this writing, no court we are aware of has ever excluded or otherwise held forensic bitemark expert testimony to be inadmissible. Perhaps that is because no court has thoughtfully compared the claims of bitemark identification to the lack of scientific foundation for those claims.
They have admitted the testimony essentially because other courts admitted it. Even a radical change in the test for admission—that is, the U. Supreme Court’s adoption of the Foorensic tetralogy—did not change that practice. A treatise on forensic scientific evidence and markw law, the lead author of which had been a forensic scientist before turning legal scholar, described these developments two decades later, saying:.