In 1998, a woman returning home from a church event near Philadelphia was grabbed from behind and raped. She could describe the man only as having a baritone voice and breath that smelled of alcohol, says the Philadelphia Inquirer. For seven years, the crime went unsolved. Then Pennsylvania required anyone convicted of a felony to have their DNA recorded in a database, deluging the state police crime lab with more than 40,000 DNA samples. One turned out to be from a convicted forger, William McKannan, 43. McKannan had no record as a violent criminal and was never considered a suspect in the 1998 crime. But his DNA matched the DNA from semen on the victim’s clothes. McKannan was arrested and is now in jail awaiting trial.
McKannan’s arrest is a harbinger of things to come. An FBI database linking all 50 states already contains the DNA of almost 1 percent of all Americans, or 2.7 million people. It has proved a useful tool for law enforcement; in Pennsylvania alone police use DNA analyses in a dozen cases a month. Civil libertarians worry that the nation is requiring ever larger numbers of people to submit genentic information even without a criminal conviction. By 2009, California will require DNA testing of every person arrested on a felony charge – not just convicted of one – a step toward making DNA records as common as fingerprints in law-enforcement files. That’s already done in Louisiana, Texas, and Virginia. Forty-three states, including New Jersey, have laws requiring convicted felons to submit their DNA.