The Washington State Patrol (WSP) crime lab in Seattle could see an uptick in cases after a rash of shootings in the Puget Sound area this week.
“It means more work for us, but we really want those cartridge casings,” said Renee Hudson, a firearms examiner at the WSP crime lab in Seattle.
Hudson is part of a team that examines a valuable piece of evidence that is often left behind at scenes of gun crimes – the shell casings.
The casings are ejected when a semi-automatic gun fires. Police collect shell casings at the scenes of crimes as evidence.
This week, there have been 10 shootings reported in King and Snohomish counties since Tuesday.
“Each firearm will leave an impression or different marking on a cartridge case,” said Hudson.
The WSP crime lab uses a machine to take digital photos of unique tool marks left on each casing by the firing pin and ejector.
They enter those images into the National Integrated Ballistic Information Network – or NIBIN – which compares them to images of shell casings collected at tens of thousands of other crime scenes across the country.
A match could lead an investigator to connect the dots to a suspect or other gun crimes on file in the NIBIN system.
“It provides a real-time investigational lead for the investigators. So, they’re able to track where a firearm is going and which crime scenes it’s linked to,” Hudson explained.
Investigators say it’s not uncommon to discover that one gun is connected to several crimes.
So far, there’s no word that any of the shootings in King or Snohomish counties this week are connected.