PRIVACY ADVOCATES SAY THE EMERGING PRACTICE TURNS RELATIVES INTO GENETIC INFORMANTS
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. In the BTK example, police had a suspect and were looking to tie him to the crime. But now, states are moving to conduct familial searches of criminal databases, looking for close-to-perfect matches with DNA from crime scenes. A partial match with a convicted criminal could implicate a brother or daughter or father of the convict. Such searches, advocates say, constitute a powerful law enforcement tool that, experts say, could increase by 40 percent the number of suspects identified through DNA.