Sep 17 2013
The Washington navy base gunman had been suffering serious mental problems and hearing voices, according to US law officials.
Sources told the AP news agency that Aaron Alexis, 34, had been treated for paranoia and a sleep disorder since August.
The US navy had not declared him mentally unfit, which would have rescinded a security clearance that he had from his earlier time in the Navy Reserves.
Family members told investigators that Alexis was being treated for his mental issues.
Alexis used a valid security pass to get inside the navy complex where he killed 12 people.
Alexis, a defence contract employee, was described as a Buddhist who had also had a violent temper, complained about the navy and being a victim of discrimination, and had several run-ins with the law, including two shootings.
The shootings in the Washington Navy Yard reignited the debate over gun control in the United States.
President Barack Obama lamented "yet another mass shooting" and promised to make sure "whoever carried out this cowardly act is held responsible." He has been powerless to get gun control legislation passed by Congress.