Aaron Alexis Navy Yard shooter

The Navy Yard gunman responsible for one of the largest mass murders in Washington D.C. history was treated for Schizophrenia, according to law enforcement officials.

Navy reservist Aaron Alexis, 34, was treated at the Veterans Administration hospital for mental problems which included hearing voices, the officials told the Associated Press.

Alexis killed 12 people and wounded 14 others before he was shot and killed by police during a shooting rampage in the nation’s Capital on Monday.

His family told the AP Alexis was a paranoid schizophrenic who heard voices in his head. Alexis carried a .45 handgun tucked in his waistband because he feared people would steal his belongings.

Apparently Alexis shared a similar obsession to Adam Lanza, the Sandy Hook gunman who killed 26 people, including 20 children, during a school shooting spree on Dec. 14.

According to a report in the UK Telegraph, Alexis was addicted to violent military-style video games.

Mayor Gray told reporters, “We don’t know what the motive [for the attack] is.”