The gunman, identified by his fingerprints as Aaron Alexis, is one of the 12 people confirmed to have died in the shooting Monday morning.
Tarrant County records show Alexis was arrested in Fort Worth in Sept. 2010 for discharging a firearm in city limits.
According to the arrest report, Alexis' upstairs neighbor called police after a hearing a pop and seeing a cloud of dust come up from her floor. The woman called police and said a bullet ripped through her floor and ceiling from the apartment downstairs. Fort Worth police knocked on her neighbor's door, but he didn't answer. As police were about to enter the apartment through force, the man, identified as Alexis, came outside willingly.
Alexis told officers he had been cleaning the weapon when it slipped and and that he accidentally pulled the trigger. He said he didn't check on his neighbor because he couldn't see light through the hole in his ceiling and that he assumed the bullet hadn't passed through her floor. He also said he thought his neighbors would assume the sound of the gunshot was a firecracker. According to police, Alexis told them he didn't answer the door initially because he assumed it was his upstairs neighbor, with whom he shared a contentious relationship.
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