Deseret News Share this story Salt Lake County Jail SALT LAKE CITY — A man who was paroled less than a year ago from the Utah State Prison after serving more than 40 years for killing a Utah Highway Patrol trooper has been arrested again. Brian Keith Stack, 60, was booked into the Salt Lake County Jail on Thursday for investigation of enticing a minor, dealing in harmful materials to a minor and sexual exploitation of a minor. Stack shot and killed UHP trooper Ray Lynn Pierson on Nov. 7, 1978, after being pulled over on state Route 20 for a minor traffic violation. Pierson was unaware that Stack was a fugitive from Illinois and had just stolen gas in Cove Fort.