By Brandon L. Garrett, a professor at the University of Virginia School of Law. Garrett’s book, Convicting the Innocent: Where Criminal Prosecutions Go Wrong, is coming out in paperback later this summer, and updates are at the book’s Facebook page here.
Yesterday the Supreme Court Justices splintered over the meaning of the Confrontation Clause in cases involving forensic DNA testing – making a muddle of an important problem and with few discernible arguments that hold much water. The case involved a sexual assault, but the Illinois State Police did not test crime scene evidence – they tested a sample of blood from the suspect and obtained his DNA profile. The evidence from the rape kit was DNA tested by an outside lab, Cellmark. The prosecutor did not call the Cellmark technician at trial, the one who did the most important DNA testing in the case, the testing that identified the DNA profile from the semen of the assailant. Instead, the prosecutor called the crime lab technician who described the defendant’s profile – and sneaking the match in through the back door, by having that technician say how it matched the profile identified in the Cellmark report. The DNA was central evidence at trial, although the victim also identified the defendant in a line-up. The defense had no opportunity to cross-examine the Cellmark analyst who did the crucial DNA work.
The case called for a straightforward application of the Court’s recent precedents in the Confrontation Clause area. Just last year, the Court held in Bullcoming v. New Mexico, a case where DUI test results were not presented by the technician who did the tests, that this was a Confrontation Clause problem. The defense must have an opportunity to cross-examine the person who did the relevant work. That decision reinforced the Court’s 2009 decision Melendez-Diaz v. Massachusetts, stating that the Confrontation Clause requires live testimony, not merely introduction of a certificate stating the conclusion of a forensic test used to identify drugs.
The new answer to the question of whether a forensic DNA analyst must testify is “maybe.”