Analyzing DNA on crime shows seems to take a matter of minutes. In reality, the actual science of analyzing a sample and turning it into a code that can be entered into a computer can be done in about 24 hours, forensic experts say. But with local, state and federal authorities working together on hundreds of thousands of DNA samples a year, processing a single piece of routine evidence can take months.
A DNA sample from Antonio Rodriguez, the Kensington Strangler suspect who had previously served time for a narcotics conviction, reached state police in October. But it wasn’t uploaded into a national database until last week.
Pennsylvania state police say because of a large backlog, it takes about 80 days for them to begin processing a DNA sample once it reaches them.
Even after the sample is analyzed, double-checked and entered into the federal database of convicted felons, which takes several days, it can sit for up to a week before being cross-referenced against the database that holds DNA samples from victims.
Deborah Calhoun is with the state’s Bureau of Forensic Services. She said searches are only run once a week because they take about 24 hours, and generate pages and pages of results. Only a few of them are true matches.
“From each of those searches a list of matches is generated,” Calhoun said. “That list can be extensive. So out of pages and pages of maybe 250 matches only maybe four of those may be legitimate hits that would require the analyst to go on and confirm it.”
Calhoun said there is a way to do a manual search if public safety demands it.
Ralph Keaton, head of the accrediting board for forensics labs, said there’s no national standard for how quickly a DNA sample should be turned around. But he does say there’s been an outpouring of federal grant money aimed at reducing DNA backlogs in recent years.
“People recognize that the quicker you can get a repeat offender off the street the better society is,” Keaton said.