DA rules officers justified in fatal Midvale shooting Salt Lake County District Attorney and last updated 2021-04-09 17:06:25-04 SALT LAKE CITY â Three police officers were justified in the The officers from the Unified and West Valley City police departments shot and killed 22-year-old Matthew Knowlden after he pointed a weapon at officers during an encounter on Sept. 18, 2020. Gill said the officers were involved in a multiagency investigation when they located a man who was a suspect who had fled from police the previous day. The suspect, who was not Knowlden, was allegedly involved in a drive-by shooting and robbery.