Catching Criminals with DNA Technology

DNA Scientists A 1997 MURDER IN KING COUNTY IS SOLVED when evidence from the scene matches the DNA of a sex offender convicted in 1986. A 1993 rape in Arizona is solved when evidence matches the DNA of a man convicted of assault in Washington in 1995.

DNA from a Tacoma rape matches DNA from a rape in Phoenix, and both samples match the DNA of a felon convicted in Arizona. Evidence from a rape in Spokane matches to a felon convicted of robbery last year.

These and other cases could not be solved using traditional investigative methods. But they have been solved in the past year, using new technology to match evidence samples from unsolved cases against DNA databanks maintained by the State Patrol Crime Laboratory and the FBI.

Increasing the Reach of DNA Technology

“DNA matching is proving to be one of the most potent weapons in our law enforcement arsenal.” Governor Gary Locke

Only violent and sex offenders must now provide DNA samples to the Crime Lab. The Governor's 2002 legislation requires additional samples from adults and juveniles convicted of any felony, plus misdemeanor stalking, harassment or communicating with a minor for immoral purposes. Correctional staff will obtain saliva swabs, instead of the blood samples now required at much higher cost. The Crime Lab will store the samples and contract to enter them into the databank as federal funding becomes available. The databank may be accessed only for criminal investigations, identifying bodies, and finding missing persons.

A Powerful Weapon Against Crime

Washington's DNA databank includes more than 33,000 DNA profiles of violent and sex offenders convicted since 1990. Recent advances in DNA identification science allow much more rapid and accurate matching of evidence from crime scenes to these databanks.

With the help of a federal grant, Washington's Crime Lab has converted its databank to the new “short tandem repeat” (STR) technology, and entered the samples into the FBI's Combined DNA Index System (CODIS). This system contains more than 460,000 samples from 34 states - to be used by law enforcement agencies nationwide. Another result of STR conversion was the identification of a suspect in some of the notorious Green River murders of the 1980s.

New Technology Breaks More “Cold” Cases

DNAIn the first 10 years of Washington's databank, there were seven “cold hits” to match crime scene evidence to offenders after traditional investigative methods had failed to identify a suspect. In 2001 alone, using the new STR matching, there have been 25 such “cold hits” —criminals who would not have been caught without this new tool.

DNA evidence most often appears in violent crimes like homicide and rape, so it makes sense to give priority to violent and sex offenders in collecting samples for possible future matching. But people with prior convictions for nonviolent crimes also commit violent offenses. For example, nine percent of drug and property offenders released from prison are back in prison within five years for violent or sex crimes. The State of Virginia found that 85 percent of “hits” from its all-felon database would have been missed if the data were limited to violent and sex offenders.

The Power of DNA Matching Will Only Grow

As the databank expands, DNA matching will become an ever more powerful weapon against crime. Law enforcement will increasingly be able to identify suspects from biological evidence at crime scenes, saving investigative time and protecting innocent people from suspicion. When DNA evidence is properly handled and stored, it is well accepted by courts, and used to convict the guilty and free the innocent.

More DNA Samples Help Solve Crimes

DNA Chart

Expanding the DNA Databank

Governor Locke won and signed legislation in March 2002 to better harness the power of DNA identification tools by:

  • Requiring all convicted adult and juvenile felons who are sentenced to confinement to provide DNA samples.
  • Providing additional in state funds for the state Crime Lab to collect and store samples.
  • Obtaining available federal funds to enter the samples in state and national DNA databanks.
  • Charging convicted adult felons a fee to help defray the cost of the databank.

Dick Van Wagenen, Governor's Executive Policy Office
Phone: (360) 902-0651
Fax: (360) 586-8380

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