The technology will be used as a last resort, police say -- and even defense attorneys may embrace the approach.
Law enforcement officials estimate the testing could increase the number of suspects identified through DNA by 40 percent.
The DNA found at a crime scene is cross-referenced with profiles already in a database. But instead of matching the suspect, whose DNA may not be on file, it may match that of a parent, child, or sibling whose DNA is on file.
Richmond defense attorney Steve Benjamin says just as he supports using DNA to exonerate the innocent, this tool can be used to develop a lead -- but not to determine guilt by association.
"It uses DNA to give the police investigative leads. That's all," he says. "It's not evidence."
Some believe the case of a Virginia Tech student murdered after leaving a concert could benefit from this testing. Morgan Harrington disappeared in 2009 after leaving a concert in Charlottesville; police found her body several months later. There has been no arrest in the case.
Members of Virginia's Forensic Science Board stress that the familial DNA testing would not be used in every case -- just when all other leads are exhausted.