Virginia prosecutors want to use a new and controversial DNA matching technique to find the man who has raped 19 women, including two teenagers in Prince William County last Halloween.
The state’s Department of Forensic Science is beginning to look into using familial DNA, which identifies suspects by linking crime scene DNA to the DNA of relatives whose profiles are in criminal justice databases.
The Virginia Association of Commonwealth’s Attorneys has asked the department to use the technique in the case of the so-called “East Coast Rapist,” whose DNA links him to attacks over the past 13 years.
Familial DNA is only used in California and Colorado. It led to an arrest in the “Grim Sleeper” case in Los Angeles last month, but critics say it could invade privacy, burden police and unfairly target minorities.
“It’s a technique that enables police to zero in on a potential offender,” said Prince William County Commonwealth’s Attorney Paul Ebert, who is investigating the Dale City rapes.
Identifying a relative of the rapist through familial DNA, Ebert said, could lead police to the culprit.
But implementing the technique would take time, said Peter Marone, director of the Virginia Department of Forensic Science. The state would need to determine whether legislation is necessary, decide what types of cases merit the test, evaluate software and train staff, Marone said.
No legislation prohibits using familial DNA, he said, but it’s also not explicitly permitted.
The department’s scientific advisory committee is discussing the issue at a board meeting that begins Tuesday in Richmond.
“In the right case, it probably could be quite effective,” said Norah Rudin, a forensic DNA consultant and committee member.
But she said familial DNA searches should be done only when there’s a reason to believe the suspect is related to someone in the database. Otherwise, she said, investigators are “just casting a blind net.”
Familial DNA is a “slippery slope,” said Dan Krane, a biology professor at Wright State University in Ohio whose term on the advisory committee ended this summer.
He said it’s hard for prosecutors to resist the technique, but it can lead to many “false positives” in a case, which invade people’s privacy and burden police.
Both Marone and experts said Virginia shouldn’t rush into using familial DNA.
If it becomes clear that the technique led to an erroneous conviction, Krane said, “you never get to do a familial search again.”
