Green River Killer - DNA Technology
"We've been using PCR for identification since 1986," said Dr. Mary Claire King, molecular biologist, University of Washington with international expertise in DNA identification of decomposed or damaged remains. King is known for her work with the families of victims of death squads in South America. PCR technology improved over the years but has been reliable enough to be used within the justice system for the past decade.
"PCR was first used here in two cases in 1991," said Fred Leatherman, a criminal defense attorney and expert on DNA forensics who teaches classes at the UW. RFLP (for restriction fragment length polymorphism) method required large amounts of DNA and relatively pristine molecules for accurate testing.
PCR was challenged by the defense as a new technique on the basis of the "Frye rule," requiring scientific method be widely accepted by the scientific community before it can be used in court. The 1991 cases went to the state Supreme Court. In the mid-1990s, PCR was accepted by the courts.
5 years ago investigators could have requested the same DNA testing that recently identified Gary Ridgway as a prime suspect.
"This has been widely available since 1996," said Howard Coleman, chief executive officer for GeneLex Corp., a Seattle DNA testing firm who has performed the "short, tandem repeats polymerase chain reaction," or STR-PCR, for the Indiana State Police crime lab for over five years.
For years local prosecutors have been sending DNA samples for STR technique to private labs such as GeneLex. "We contract out quite a few DNA cases," said Tom McBride, executive secretary of the Washington Association of Prosecuting Attorneys in Olympia.
In February 2000, Barry Logan said, the Forensic Laboratory Services Bureau run by the Washington State Patrol were using a new kind of DNA test with the ability to accurately amplify DNA from one cell or a single fragment of DNA.
So why did it take 1.5 years to get results?
Scientists at the Washington State Patrol's crime lab have been able to do this form of DNA testing for about the last year and a half. "They are understaffed, overworked and underpaid," said King County Prosecutor Norm Maleng. "Both (King County) Sheriff Reichert and I have met with Gov. (Gary) Locke to ask him to commit additional funds to build a first-rate crime lab," he said.
Sgt. John Urquhart, spokesman for the King County Sheriff's Office, agrees detectives could have requested STR testing years earlier.
Cases with existing trial dates take priority over older cases not going to trial. March 2001, "When we were approached by the sheriff's office to do this (new tests on the Green River case), we assigned a scientist to it even though this meant we had to shove some of the higher priority cases out of the way," Dr. Barry Logan, forensics crime lab director, said.
The Sheriff's Office had to sort through 10,000 items of evidence collected over the years to determine which were most amenable to this new DNA testing.
For the tests to be valid in court, laboratory scientists need to be certified. Certification requires classes in molecular biology, genetics and biochemistry.
The lab had a huge backlog of DNA from felons to enter in the database, current cases with suspects in custody or with trial dates coming up. The lab has a 620 case backlog. 1/2 to 2/3rds of the cases are rush orders for court cases.
Fred Johnston, chairman of the state Forensics Investigation Council, said "We can now get a good DNA sample off a doorbell. But it doesn't do any good if we don't have the staff to do the case work."
Ed Blake, director of Forensic Science Associates in Richmond, CA, said "People have to realize that physical evidence in these cases is priceless and irreplaceable." If they sent the DNA out for testing whenever there was a new technique, they could eventually lose evidence.
August 2001, Logan submitted a plan to meet increasing demands for DNA testing. He's asked for $4 million to hire about 40 more scientists and improve equipment and facilities.
Copyright Kari Sable 1994-2011