Law Proposed to Collect DNA from Shoplifters

DNA samples are usually collected by swabbing inside the cheek.

The American Civil Liberties Union and criminal defense groups have cried foul, calling the bill unconstitutional. Another question they might raise: Is it worth it?

Each person's DNA is unique, representing the software of that person's life. DNA samples collected at crime scenes can, after a tedious process in the lab, be matched to samples on file to positively identify suspects.

While DNA identification can be more effective than fingerprinting in some cases, it's not as seen on TV.

"Just because you can run an analysis doesn't mean you'll get results," explains Tina Delgado, forensic DNA examiner in the FBI's DNA Analysis Unit. "Sunlight, heat, humidity, and age can all damage DNA. We have successfully analyzed material that had been in police evidence lockers at room temperature for decades, but DNA can go bad if left out in the sun for even a few days."

Meanwhile, labs are becoming overloaded.

More than a dozen states allow law enforcement to collect DNA from suspects before they are convicted.

The U.S. government last year announced plans to collect DNA samples from all citizens arrested in connection with any federal crime, as well as from many immigrants detained by federal authorities, according to the Washington Post. The approach was expected to add more than a million DNA samples a year to the rapidly growing federal DNA database of bad guys.

"It is good technology. It solves crimes," said Don Pierce, executive director of the Washington Association of Sheriffs and Police Chiefs, in the Times article. "We take fingerprints at the time of arrest, which in many ways is a lot more intrusive."

But in Los Angeles, the police department recently was found to have in cold storage nearly 7,000 untested DNA samples from sexual assault cases. Last year the department let the deadline pass for prosecuting some 200 potential sexual assault cases without ever testing DNA evidence on file that might have resulted in convictions.

• DNA Crime Lab Analysis: TV vs. Reality
• The Reality of Fingerprinting Not Like TV Crime Labs
• Crime News and Information

Robert Roy Britt is the Editorial Director of Imaginova. In this column, The Water Cooler, he takes a daily look at what people are talking about in the world of science and beyond.