Police have identified the gunman in Saturday's Columbia, Maryland mall shooting as 19-year-old Darion Aguilar.
It took hours to identify Aguilar since he was carrying ammunition and a backpack containing crude homemade explosives. More ammunition and other evidence was found when officers searched Aguilar's College Park, Maryland home Saturday night.
Howard County Police Chief William McMahon said Sunday night they had taken a journal from the house, but Aguilar did not give any specifics about what it contained. He did express some general unhappiness, but police are still unsure of a motive in the shooting.
Aguilar arrived at the Mall in Columbia in a suburb of Baltimore and Washington, D.C. just after 10 a.m. and used a 12-gauge shotgun to kill two store employees an hour later before killing himself.
Investigators are trying to determine whether Aguilar knew either of the victims, 21-year-old Brianna Benlolo of College Park and 25-year-old Tyler Johnson of Ellicott City, Maryland. Both worked at a skateboard shop called Zumiez.
Five others were injured, including one shot in the foot. They were treated and released from the hospital.
Police searched the mall with dogs and stores will remain closed through Tuesday.