In April 2009 I blogged about the case of John Kunco, a Pennsylvania man convicted of a rape in 1992 based mostly on the testimony of a bite mark expert. The Innocence Project asked the Pennsylvania Supreme Court to grant Kunco a new trial, based mostly on the 2009 National Academy of Sciences report on forensic evidence that found no scientific evidence to support the proposition that it's possible to trace bite marks in human skin to one person to the exclusion of all others.

A quick summary from my post last year:

Two forensic odonotologists, or bite mark experts, named Michael N. Sobel and Thomas J. David testified that they were able to use ultraviolet light to isolate and photograph the woman’s wounds. Based on that photograph they were able to match the wounds to Kunco’s teeth, to the exclusion of anyone else. Their testimony grows more absurd when you consider that the photograph was taken five months after the rape, after the wounds had mostly healed.

Sobel and David wrote an article about their analysis in the Kunco case for a 1994 edition of the Journal of Forensic Sciences. In that article, they explain that “the technique used followed the recommendations developed by other odontologists.” One of the two footnotes to that sentence points to an article written by none other than . . . now-disgraced Mississippi bite mark expert, Dr. Michael West.

There's no question that bite mark testimony was critical to securing Kunco's conviction. The excellent new Bite Mark Evidence blog notes this passage from the prosecutor's closing argument:

[T]here’s no way, no way on this earth, for Mr. Kunco to explain how his tooth marks got on Donna Seaman’s shoulder unless you accept the fact that he’s the one who attacked and brutalized Mrs. Seaman. That’s the only explanation, ladies and gentlemen. That’s why the evidence is better than fingerprints or hair samples … [T]he bite mark on Danna Seaman’s shoulder was as good as a fingerprint. And I submit to you it was that, ladies and gentlemen, for all intents and purposes. Ladies and gentlemen, I’d submit to you that John Kunco should have just signed his name on Donna Seaman’s back, because the bite mark on Donna Seaman’s shoulder belongs to John Kunco.

There was no other physical evidence linking Kunco to the crime scene.

I missed the decision when it came out, but last October Pennsylvania Jude Rita Donovan Hathaway refused Kunco's petition for a new trial. Hathaway acknowledged the limitations of bite mark testimony, and that the reliability of said testimony has been called into question (to put it mildly). So why did she deny Kunco relief? 

To get a new trial post-conviction, you have to show that you've discovered new evidence that could not have been discovered at the time of trial, and that given the new evidence, no reasonable juror would convict you. But in Pennsylvania, you also need to file your petition within one year of discovering the new evidence.

Kunco did file his petition within one year of the release of the NAS report. But Hathaway ruled that the research upon which the NAS report was based was published in other sources much earlier. Kunco, she ruled, should have filed within a year of the publication of that research. In other words, the expert testimony used to convict Kunco may well have been fraudulent, but Hathaway is going to keep him in prison anyway, basically on a technicality (this is similar to what's happening in the Eddie Lee Howard case).

The NAS report was a synthesis of research across nearly every forensic discipline. It was a landmark report, commissioned by Congress in response to the rash of DNA exonerations. The cruel conundrum here is that when other people convicted on bite mark testimony have filed for relief and cited the publication of an article in a narrowly-read scientific journal (also like Eddie Lee Howard in Mississippi), they've been denied on the argument that a peer-reviewed article here and there isn't enough of a scientific consensus to overturn a jury verdict, especially if you already challenged the state's bite mark expert at trial. If Kunco had filed shortly after that first journal article disputing bite mark evidence was published, and had he lost, in most states he would then be barred from making additional post-conviction claims on the same topic, even if more articles then came out showing a consensus that he was right.

Hathaway then goes on to misstate the findings of the NAS report. She writes:

The [NAS] Report does not, however, conclude that the use of bitemark analysis and comparison has lost general acceptance in the scientific community of forensic odontology. Rather, it specifically acknowledges that "the majority of forensic odontologists are satisfied that bite marks can demonstrate sufficient detail for positive identification."

Two problems here. First, Hathaway is only quoting the first part of that sentence. Second, she has also taken the entire sentence out of context. Here's the complete sentence, in proper context:

Although the majority of forensic odontologists are satisfied that bite marks can demonstrate sufficient detail for positive identification, no scientific studies support this assessment, and no large population studies have been conducted. In numerous instances, experts diverge widely in their evaluations of the same bite mark evidence, which has led to questioning of the value and scientific objectivity of such evidence.

Bite mark testimony has been criticized basically on the same grounds as testimony by questioned document examiners and microscopic hair examiners. The committee received no evidence of an existing scientific basis for identifying an individual to the exclusion of all others. 

Leaves quite a different impression, doesn't it? The disconnect here is that the NAS report is criticizing the entire field of forensic odontology. It isn't surprising that a majority of forensic odontologists, many of whom have given bite mark-matching testimony themselves, would think that bite mark matching is legitimate science. It's only slightly less absurd than saying that palm reading is a legitimate science because a majority of clairvoyants, some of whom are palm readers, say so. (I use the word slightly here because there are legitimate areas of forensic odontology, such as using dental records to identify human remains.)

Hathaway is also misleading here:

Even the defendants' experts, in their remarkably uniform affidavits, state: "the NAS Report did not invalidate bite mark identification entirely," nor did it report that bite mark identification fell into the realm of junk science" . . . 

I guess that's true. The NAS report did not specifically use the phrase junk science. It's also true that the report didn't "invalidate bite mark identification entirely." Instead, the report concluded that with more research, bite mark identification might someday be useful as an investigative tool, and, in limited circumstances, might have some value in excluding suspects. (Such as if there's a fresh, easily identified human bite mark on the body, and the chief suspect has no teeth.) But as noted above, the report was decisive in its conclusion about the use of bite mark analysis to identify one suspect to the exclusion of all others: It simply isn't backed by any serious science. And this is exactly how bite mark evidence was used in Kunco's case.

One other thing. As noted, the expert witnesses in Kunco's case used a method of analysis used by disgraced Mississippi bite mark specialist Michael West. West has been cast out from the forensic odontology community. So even within the already-questionable field of bite mark matching, West and his methods are considered quackery.

Hathaway's ruling here is appalling, as is the state's willingness to keep a man in prison based on testimony we now know to be utterly unsupported by science. Judges and prosecutors with any sense of justice or shame ought to be tripping over themselves to give all of these bite mark cases a thorough review. Instead, they're throwing up procedural and technical roadblocks to prevent the convicted from getting a fair trial untainted by crappy science.