Colorado D.A. offers Philadelphia help in Kensington strangler case

Denver District Attorney Mitchell Morrissey says he wants to help Philadelphia police catch the Kensington strangler using a new forensics technology known as familial DNA.

The technique can help zero in on suspects by using DNA to identify their close relatives.

Familial DNA has helped police crack several cold cases in England; last summer, it helped capture a suspected notorious California serial killer.

So far, the Kensington strangler has killed three women. Samples from the crime scenes show a common DNA signature, which could be used to seek relatives.

"When I read that they connected a third woman's death to this same DNA profile, I couldn't just sit on my hands," Morrissey said.

The technology needs special software, and Morrissey has offered Colorado's version for free, even offering to send experts here to install it.

He said he made the offer in e-mails to Philadelphia District Attorney Seth Williams, as well as to Police Commissioner Charles H. Ramsey, Fraternal Order of Police president John J. McNesby, and Mayor Nutter.

Williams and McNesby responded, Morrissey said, promising to forward the offer to detectives.

"I'm aware of the technology, and I've personally reached out to the FBI," Deputy Police Commissioner William Blackburn said. "We're going to explore the possibility of using this."

Scientists who have studied familial DNA say Philadelphia should take Colorado's offer seriously.

"This is exactly the kind of case that they should consider the familial searching method for . . . assuming they have a good, complete DNA result, and they've exhausted other reasonable leads, and there's an ongoing threat to public safety," said Frederick Bieber, a geneticist at Harvard Medical School.

The technique can sift through databases of known offenders and find people likely to be close relatives of a person whose DNA is found at a crime scene.

Some critics see potential civil-liberties violations. The technology can identify people with family ties to a sample at a crime scene, said Sheldon Krimsky, a Tufts University professor who studies science and ethics. "All of a sudden, these people's families are suspects," he said, even if they do not have any other ties to the crime.

Former Assistant U.S. Attorney Chris Asplen disagreed, saying that family members who come up in DNA searches are not necessarily suspects but could help lead to one.