August 4, 2007

Beware the bite-mark expert

Is forensic odontologist putting innocent people on death row?

With our increasingly crime-centered culture comes the "CSI Syndrome" of glorification of all things forensic. Unfortunately, it is sometimes hard for laypeople to distinguish valid science from the junk, and good experts from charlatans.

This is especially true in newly emerging fields such as "forensic odontology," in which dentists testify as expert witnesses about bite-mark patterns.

The spotlight on wrongful convictions is shining its beam on forensic odontology as – in the words of one legal scholar – "the poster child for bad forensic science."

In an expose in the Chicago Tribune a few years ago, journalists Flynn McRoberts and Steve Mills called the field "a case study" of the ease with which "forensic science's false aura of infallibility can distort the adversarial system of American justice."

Ask 10 dentists to identify a suspect from bite marks, and six of them will point to an innocent person, according to one informal study conducted at a convention workshop back in 1999. Indeed, odontologists often don’t agree on the most basic issue of all – whether a mark on a victim’s body is even a bite mark.

Ask who is the worst culprit of all, and you’re likely to hear the name of Michael West of Mississippi. He's testified in dozens of cases and helped to send many people to prison, including at least five to death row. He’s been the subject of exposes on 60 Minutes and in Newsweek and the National Law Journal.

Later this month, his testimony will be at the center of a hearing regarding a new trial for Kennedy Brewer, convicted of the 1991 murder of his then-girlfriend's 3-year-old daughter.

At Brewer's original trial, Dr. West testified that he found 19 bite marks on the girl's body that matched Brewer’s teeth. A defense expert countered that the marks were actually insect bites, but the jury believed the charismatic Dr. West.

The new hearing is a result of new DNA technology that didn’t exist at that time. Analysis of semen found in the girl's body revealed that it came from two separate men - neither of them Brewer.

Dr. West has taken the field of forensic odontology to "bizarre, megalomaniacal depths," according to an expose yesterday on Fox News. He has "invented a system he modestly calls 'The West Phenomenon.' In it, he dons a pair of yellow goggles and with the aid of a blue laser, he says he can identify bite marks, scratches, and other marks on a corpse that no one else can see - not even other forensics experts. Conveniently, he claims his unique method can't be photographed or reproduced, which he says makes his opinions unimpeachable by other experts."

The case points to the need for both courts and professional organizations to more vigilantly police expert witnesses.

The stakes are enormously high - both for potentially innocent suspects and for the credibility of the forensic sciences. As Fox reporter Radley Balko argues:

"The Kennedy Brewer case highlights a serious flaw in our adversarial criminal justice system — the use of expert testimony in complicated, advanced scientific fields. A charlatan like Dr. West, who has little respect from his peers, can with charisma and personality convince a jury to take his word over that of an expert far more careful and deliberate in his analysis. In some cases, indigent defendants can't afford to hire their own experts at all, leaving a state's expert like West as the only testimony on the available forensic evidence."

photo credit: "selfCTRL" (Creative Commons license)