DNA testing is one of the most rapidly changing technologies.
The director of the Philadelphia Police Department's Forensic Science Bureau is trying to take the resource to the next level to solve crime by using kinship testing.
"It could be a waste of time if you don't do it correctly," said Dir. Michael Garvey.
When it comes to a crime scene, investigators are looking for direct DNA matches. However, Garvey says it's possible to track down a suspect by first identifying a relative - a person who most likely didn't have anything do with the crime, but could give police a lead in a case.
"We are looking at is this close enough to a person that could be related to the real perpetrator. It's going to generate a candidate list of possible people," said Garvey.
That relative's DNA would already have to be in a database like the one operated by the Pennsylvania State Police.
It holds the DNA of hundreds of thousands of convicted felons.
Right now State Police don't have a policy to allow kinship searches, but there's a piece of legislation making its way through Harrisburg that could make it happen.
Philadelphia Police Commissioner Charles Ramsey says he is well aware of the criticism and privacy concerns, but kinship testing could be instrumental in exonerating people and cracking cold cases.
For example, the Fairmount Park rapist who first struck 10 years ago remains at large.
"It's not grown cold in terms of our interest, it's just we haven't gotten any fresh leads in a long time and that's exactly the kind of case and circumstances in which you want to resort to something like this," said Ramsey.
The work Garvey is doing could have national implications. Commissioner Ramsey brought the civilian in from Washington D.C. two years ago.
Garvey got his start as a forensics investigator for the D.C. Medical Examiner's Office and spent seven years with the FBI. He also spent eight years with the CIA - a stint that is so classified, he's still not allowed to say what he did for the agency.
"He brings a lot of experience and a lot of expertise and that's exactly what you need in a big city crime lab," said Ramsey.
While these kinship tests require more resources, time and money, the commissioner says it's all worth it to get criminals off the streets.