Solving crimes with DNA — the Supreme Court gets it right

The following editorial appeared in the Chicago Tribune on Wednesday, June 5:

Modern DNA analysis has been a godsend to the criminal justice system. By making it possible to identify individuals who leave behind biological material at crime scenes, it allows police and prosecutors to accurately implicate the guilty, particularly in murders and rapes. It has also exonerated hundreds of people who were wrongly convicted because of misleading evidence or false claims.

The potential of this tool is only starting to be realized fully. Thanks to a U.S. Supreme Court decision Monday, that progress can proceed under sensible rules but no undue impediment.

Under Maryland law, anyone arrested for a serious crime is subject to a cheek swab for DNA, which is checked against a database of samples. In 2009, Alonzo King, arrested for brandishing a shotgun, was matched to DNA recovered from a 2003 rape victim. He was convicted of rape and sentenced to life without parole.

King appealed, arguing that taking his DNA was an unconstitutional search, since the police had no basis to suspect him of the rape. The Maryland Court of Appeals agreed, concluding that because he had not been convicted, King had a weighty and reasonable expectation of privacy against warrantless, suspicionless searches making the sampling invalid.

But in a 5-4 decision, the U.S. Supreme Court said that taking DNA from felony arrestees is permissible. It took the view that such material is valuable in establishing the identity of the person arrested, which helps in assessing if he should be granted bail. Someone implicated in a murder, for example, would warrant different treatment from someone whose DNA doesn't match any in the database.

The dissenting justices argued that the real purpose of the swab is to let law enforcement get evidence of crimes for which suspects have not been arrested. That may be true but it is also true of fingerprints, which police have been taking from suspects for decades without any objection from the Supreme Court.

As for the alleged invasion of privacy, keep in mind we are talking about people who have been arrested and who may be strip-searched to make sure they are not carrying weapons or contraband. The expectation of privacy in a jail cell is minimal. Taking a DNA sample is not appreciably more intrusive than taking a fingerprint and is even more useful. It's hard to think of a good reason fingerprinting should be allowed but DNA swabs should be forbidden. The dissenting justices seem to be more suspicious of the latter only because it's new and relatively unfamiliar.

There are protections for privacy written into the Maryland law. It applies only to those arrested for crimes involving violence or burglary. Police are not allowed to put the samples into the database unless and until the suspect has been arraigned. If the defendant is not convicted, the sample is destroyed. And the DNA may not be used for any other purpose.

Illinois' law allows for the collection of DNA after an indictment. Bills to broaden it to include those arrested for serious crimes have been introduced over the years. The court's verdict should spark interest in making greater use of a tool that helps only the innocent and endangers only the guilty.

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Solving crimes with DNA — the Supreme Court gets it right