The former Navy reservist who slaughtered 12 people at the Washington Navy Yard had been “hearing voices” and was being treated for mental problems in the weeks before the shooting rampage, but was not stripped of his security clearance, officials said.

The Washington massacre gunman had serious mental problems and suffered fits of rage, but was still able to hold an official security clearance for the complex where he killed 12 people.

The Washington massacre gunman used a valid security pass to get inside the navy complex where he killed 12 people but the motive for the shootings was still a mystery, investigators said.