He was a church-going father of two, and for more than 30 years Dennis Rader eluded police in the Wichita area, killing 10 people and signing taunting letters with a self-styled monogram: BTK, for Bind Torture Kill. In the end, it was a DNA sample that tied BTK to his crimes. Not his own DNA. But his daughter’s.
Investigators obtained a court order without the daughter’s knowledge for a Pap smear specimen she had given five years earlier at a university medical clinic in Kansas. A DNA profile of the specimen almost perfectly matched the DNA evidence taken from several BTK crime scenes, leading detectives to conclude she was the child of the killer. That allowed police to secure an arrest warrant in February 2005 and end BTK’s murderous career.
The BTK case was an early use of an emerging tool in law enforcement: analyzing the DNA of a suspect’s relatives. […]
[…] As things stand in some states, lab analysts who discover a potential suspect in this way may not be permitted to share that information with investigators. Such a policy, said William Fitzpatrick, a New York state district attorney, “is insanity. It’s disgraceful. If I’ve got something of scientific value that I can’t share because of imaginary privacy concerns, it’s crazy. That’s how we solve crimes.”
But the technique is arousing fierce objections from privacy advocates, who maintain that it turns family members into genetic informants without their knowledge or consent. They complain that it takes material collected for one purpose and uses it for another. And with the nation’s DNA database disproportionately comprised of minority offenders, they say, it amounts to placing a class of Americans under greater scrutiny merely because their relatives have committed crimes.
“If practiced routinely, we would be subjecting hundreds of thousands of innocent people who happen to be relatives of individuals in the FBI database to lifelong genetic surveillance,” said Tania Simoncelli, science adviser to the American Civil Liberties Union.