NEW : It 's unclear how Alexis got a shotgun past security . These individuals , Alexis police , had followed him to three hotels in the area -- including talking to him through walls and the floor and using `` some sort of machine '' to send vibrations through the ceiling that prevented him from falling asleep . NEW : A Washington police officer ended the 30-minute spree by killing Alexis , mayor says . Alexis had issues in the Navy and with police , but still had security clearance . New :
NEW : It 's unclear how Alexis got a shotgun past security . NEW : A Washington police officer ended the 30-minute spree by killing Alexis , mayor says . Alexis had issues in the Navy and with police , but still had security clearance . New :