Investigators are trying to determine the motive behind the shooting deaths of four people in the San Fernando Valley Thursday, including a veteran LAPD SWAT officer. Police killed the gunman at the end of the overnight standoff at the man's home. Police have not released the names of the gunman or his victims. The SWAT officer was the first killed in the line of duty in the 41-year history of the elite unit. KPCC's Frank Stoltze reports.