More details have emerged about the troubled life of Aaron Alexis, the man who allegedly shot 12 people to death Monday morning at the Washington Navy Yard. In addition to his discharge from the Navy and multiple arrests, Alexis reportedly had a long history of mental illness.

Sources told NBC News that Alexis had been treated multiple times for psychological issues like anger, sleep deprivation, and paranoia, and the Associated Press is reporting that Alexis was treated by the Veterans Administration for “hearing voices,” among other problems.

The mental illness issues, coupled with his “general discharge” from the Navy in 2011 (reportedly for a “pattern of misconduct”) [UPDATE: The Washington Post is now reporting that Alexis's discharge was "honorable"] and arrests for violent behavior involving firearms probably should have prevented him from gaining clearance to the secure-areas like the Navy Yard, but they weren't; Alexis, who had just moved to Washington D.C. this month to work as an hourly computer contractor for a company called The Experts, had “legitimate access” to the naval headquarters, according to an FBI spokeswoman.

Read it at Gawker.