In this week’s New England Journal, Mark Rothstein takes up the question of forensic DNA testing:

On December 21, 2004, Brandon Moon was released from prison in El Paso, Texas, after having served 16 years of a 75-year sentence for three counts of aggravated sexual assault. Moon, who was 43 years of age at the time of his release, had been convicted in 1988 on the testimony of the three victims, who had had only a fleeting or partial view of their assailant. In 2004, after undergoing DNA testing, Moon was excluded as the contributor of the DNA collected after all three rapes. As a result, Moon became the 154th person in the United States to be exonerated on the basis of DNA evidence that came to light after the person was convicted for a crime…

irst, do these cases of wrongful conviction represent the tip of the iceberg, indicating the existence of deeper structural problems in the criminal justice system? As a study by Gross et al. revealed,2 most of the exonerations that have occurred since 1989 involved faulty eyewitness testimony, as in the case of Brandon Moon, coerced or false confessions, or perjurious testimony by prison inmates. Other cases involved poor crime-scene processing or poor evaluation of evidence by forensic laboratory workers, ineffective defense counsel, or even police and prosecutorial misconduct. Studies of errors in these cases often indicate the presence of systemic problems in forensics, law enforcement, or the criminal courts.3 For example, officials in several states ordered the review of hundreds of convictions after they determined that state and local crime laboratories might have made numerous errors in handling and testing evidence or, worse, might have deliberately falsified the results or interpretations of forensic testing.

Second, aside from those already exonerated, how many other innocent people have been convicted of serious crimes and have served, or are now serving, long prison sentences or are facing execution in one of the 38 states that permit capital punishment? Although there may not always be crime-scene evidence available for DNA testing, new federal legislation should make DNA testing more widely available to those who have been convicted. On October 30, 2004, President George W. Bush signed the Justice for All Act of 2004, which grants any inmate convicted of a federal crime the right to petition a federal court for DNA testing to support a claim of innocence. The law provides funding to the states to preserve evidence and to make DNA testing available to those who have been convicted by the state as well. It also increases the financial compensation of wrongfully convicted federal prisoners. Under Texas law, Brandon Moon is eligible for up to $25,000 for each year he was wrongfully imprisoned. Many states, however, have no provision for compensation.

Third, what is the proper role of DNA evidence in criminal investigations? DNA has the power not only to exculpate but also to inculpate. Forensic DNA analysis was first used in the United Kingdom in 1985 to solve two related sexual homicides. The use of such evidence soon became internationally accepted as a method for linking suspects with crime-scene evidence. In 1990, the Federal Bureau of Investigation established a series of federalstate forensic DNA data banks, called the Combined DNA Index System, or CODIS. In every state, certain convicted felons are required to submit a sample of DNA to be typed and the profile entered into a computerized data bank. Law-enforcement officials can then compare the DNA profiles obtained from evidence from a crime scene with all the DNA profiles in the local, state, or national system.

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