December 2008 Archives

December 18, 2008

Bitemark Evidence Needs Orthodontia


Bitemark evidence is a tool that prosecutors sometimes use to connect defendants to crimes. The testimony of a bitemark expert (who carries the fancy, jury-impressing title of "forensic odontologist") usually goes something like this: "I compared the teethmarks found on the victim's right arm with the defendant's dental prints.  In my opinion, a match exists; the defendant was responsible for the teethmarks." 

Though judges routinely admit bitemark testimony, recent studies have undermined its reliability.  Unlike the generally-accepted principle that fingerprints are unique, the uniqueness of dental patterns has never been established. Moreover, bitemark experts usually have to base their conclusions on fragmentary patterns -- say, the marks left by a few teeth. Finally, the proficiency of bitemark experts is uncertain because they have never been scientifically studied.  Thus, it's no surprise that a number of defendants who have been cleared by DNA analysis after they have begun serving their sentences were convicted partly on the basis of mistaken bitemark evidence.

In the future, criminal defense attorneys will no doubt more aggressively challenge the admissibility of bitemark evidence. As "gatekeepers," judges have to remember that prosecutors who want to rely on bitemark evidence have the burden of establishing the reliability of its underlying principles.  If they cannot do so, judges should disregard the fancy trappings of forensic odontologists (advanced degrees, publications, professional associations, good molars) and tell them to bite the dust.

December 10, 2008

The U.S. Supreme Court Considers Whether the Constitution Requires Forensic Lab Experts to Testify at Trial

In the 2004 "Crawford case", the U.S. Supreme Court interpreted the Sixth Amendment's Confrontation Clause to require prosecutors to present live witnesses rather than hearsay whenever the hearsay was "testimonial." The decision has given rise to lots of commentary and court opinions (many of them conflicting) about whether particular types of hearsay are testimonial.  For example, if a domestic violence victim makes an emergency call to a 911 operator, the victim's statements are likely not to be testimonial, meaning that prosecutors can, if necessary, offer a transcript of the call into evidence if the victim refuses to come to court and testify.  On the other hand, if the domestic violence victim talks to a police officer once the emergency is over, the victim's statements are testimonial. If the victim refuses to testify, the prosecutor cannot call the police officer as a witness to testify to what the victim said.

One of the elephants in the Confrontation Clause room is whether lab reports are testimonial.  Every day, hundreds of doctors and other technicians conduct autopsies, test substances to determine whether they are illegal drugs, determine the alcohol context of blood or urine, etc.  They prepare reports of their findings and before Crawford most courts routinely admitted these reports into evidence at trial under long-established hearsay exceptions for business or official records. But if these reports are testimonial, defendants would have the right to insist that the report preparers testify in person.  The ramifications of such a result are potentially huge. If forensic experts have to testify, at the very least trials become longer and lab backlogs will continue to grow because experts who are testifying (or, more likely, waiting to testify) are not conducting tests.

Sometime in early 2009, the U.S. Supreme Court will likely issue an opinion addressing these issues.  The case is Melendez-Diaz v. Massachusetts, and the Court heard arguments in the case in November 2008.  Forensic lab reports certainly look testimonial in that they are prepared by government officials who usually are aware that they may be offered into evidence at trial.  Prosecutors counter that lab reports are not testimonial because they are objective, especially since many of them are simply machine-generated.  Prosecutors also argue that if defendants really want report preparers to testify, the defendants can call them as their own witnesses.

The outcome of Melendez-Diaz is likely to have a huge impact on the day-to-day functioning of the criminal courts.  My prediction: Since the Supremes have been Confrontation Clause-happy, they will rule that most lab reports are testimonial.  

December 1, 2008

Convicting Date Rapists and Domestic Abusers: Women May Be Their Own Worst Enemy

Date rape and domestic violence are two of the most serious crimes in which the victims are almost always women. Yet the conviction rate of the perpetrators of these violent acts is abysmally low. Unfortunately, the all-too-frequent behavior of the victims of these crimes contributes to the low conviction rate.

As I mentioned in an earlier post, women who have been subjected to domestic violence very often refuse to cooperate with police and prosecutors. For example, they may recant earlier complaints, or simply disappear when their attackers are put on trial. And recent changes in evidence rules make it almost impossible for prosecutors to win convictions unless abused women appear at trial and describe what happened while under oath.  

As for date rape, a recent study, as reported in Self magazine, indicates that when a woman has known her alleged assailant for less than 24 hours, 43% of rape trials end with convictions. However, when a woman has known her alleged assailant for more than 24 hours, the conviction rate falls to 35%. By contrast, the conviction rate in so-called "stranger rape" cases (when a woman has had no prior contact with her alleged attacker) is 68%.

What type of female behavior contributes to the low conviction rate in date-rape cases? Often, date rape victims fail to report the crimes immediately to the police, nor do they go to a hospital for a rape exam and toxicology test. Moreover, in date rape situations the women have often been drinking alcohol shortly before the alleged rape occurred. Finally, in some cases, women have even gone out on post-rape dates with their attackers (perhaps hoping for an apology, or to validate their suspicion that they had been raped on the earlier occasion). Needless to say, defense attorneys can emphasize these types of behavior when arguing that there's reasonable doubt that a rape took place.

The victims' behavior that makes it difficult for prosecutors to convict domestic abusers and date rapists may be psychologically understandable. For example, domestic abusers may  silence victims with threats of future violence, and date rape victims may be in denial before they are ready to report what happened. Nevertheless, under the glare of the adversary system, these types of behavior are powerful impediments to conviction.