WASHINGTON - More and more cold cases are being solved with the help of DNA testing.
Just last month, DNA evidence helped close a 40-year-old Richland murder investigation. This week, Seattle police solved a murder from over 50 years ago with the help of DNA and a family tree.
Every so often, cold cases are re-examined by the detectives working on the case. When reviewing cases they look for any new biological evidence that has been overlooked that the lab and new technology can help solve. At times, detectives will even re-submit evidence that has already been tested but new technology may be able to shed more light on that piece of evidence.
The DNA section of a crime lab is usually more focused on violent crimes such as homicide, assault, robbery and sexual assault.
DNA analysts help detectives determine which items of evidence can be best used for testing as it relates to the crime. A DNA analysis includes different methods such as bodily fluid screenings which involves blood testing, saliva testing and more.
Then analysts proceed through a multi-step process to find out if there is a DNA profile available for comparison.
Generally if there is a victim such as in a homicide, analysts would want the victims profile along with a sample from the suspect.
When it comes to cold cases, the biggest problems that DNA analysts will run into is having to re-examine evidence that was not handled or stored properly over the years.But if it has been packaged properly DNA evidence can last for a very long time.
At the Washington State Patrol Crime Lab they regularly get decades old cases that they are still able to get DNA profiles from eligible for CODIS. This is an FBI software that blends forensic science and computer technology and allows analysts to compare DNA profiles from previous crime scenes.
In 2018 alone, the crime lab received over 600 CODIS hits; although this does not necessarily mean it will solve the case it does provides investigative information for the detectives.