The man who shot and killed 12 people Monday at the Washington, D.C. Navy Yard had received treatment for mental health issues, according to U.S. media reports.
Aaron Alexis, age 34, had been treated for paranoia, hearing voices, and sleeplessness, said an Associated Press report.
Authorities say the military contractor had a valid pass into the Washington Navy Yard, where he entered Monday morning and went on a shooting rampage that killed 12 people before being shot and killed himself by police.
In August, Alexis sought psychological help from the U.S. Department of Veterans Affairs.
Last month he called police from a Rhode Island hotel and complained he kept hearing voices.
He told officers he believed people were following him and “sending vibrations into his body,” according to a Newport police report.
He said he had changed hotels twice to evade his pursuers, who he claimed were using “some sort of microwave machine” to keep him from sleeping.
Washington, D.C. remained in a state of shock and mourning Tuesday.
Witnesses say Alexis entered Building 197, sprayed bullets into a hallway, and then fired from a balcony down at workers into an atrium.
The attack ended when police stormed the building and shot him dead.
Authorities say Alexis was armed with a shotgun which he had legally purchased in Virginia, as well as a handgun they believe he may have taken from a guard inside the naval complex.
Previous media reports said he had also used an AR-15 semiautomatic rifle, but on Tuesday officials said that although the weapon was found at the scene, they now believe Alexis neither carried nor used it.
Authorities said they believe Alexis acted alone, and that all 12 victims have been identified.
Alexis evidently had a card granting him access to the building, in spite of his mental health issues and previous run-ins with the law. He left the Navy under a general discharge in 2011, a status that suggests misconduct.
“It really is hard to believe that someone with a record as chequered as this man could conceivably get, you know, clearance… to be able to get on the base,” said Washington D.C. Mayor Vincent Gray to CNN.
The Washington Post reported that Alexis had been cited for insubordination, disorderly behavior, and excessive absences from work at least eight times during his Navy career.
The media also reported that he had had several gun-related brushes with the law.
The Washington D.C. Navy installation contains the headquarters for Naval Sea Systems Command, which builds and maintains ships and submarines for the Navy. Image/Reuters