"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.