Details about Monday's mass shooting at the Navy Yard in Washington, D.C., are still emerging, but we have learned quite a bit more about exactly what happened, who the shooter is and who the victims are.

On Monday morning Aaron Alexis (inset picture above), a defense contractor and former Navy reservist, entered the Navy Yard using a Common Access Card (which is given to contractors), bringing with him at least one gun that he kept hidden in his car. Once inside, he shot a police officer and another person outside of Building 197. He then entered the building, made his way to a fourth-floor balcony overlooking a cafeteria, and opened fire on those seated below eating breakfast.

In total, Alexis killed 12 people and wounded at least eight more. He was shot and killed at the scene by police. Authorities found three weapons on Alexis: a shotgun, a semiautomatic pistol and a third that was either an AR-15 assault rifle or another handgun. (Initial reports said that Alexis had used the assault rifle, but that information may be incorrect.)

Alexis had a history of violent behavior and mental illness. NBC reports that he had been treated for psychological issues including sleep deprivation, anger and paranoia. He may also have heard voices in his head, according to the Associated Press. Alexis was arrested twice on gun-related charges, once in Seattle in 2004 after he shot out the tires of a co-worker and once in Fort Worth, Texas, in 2010, when he shot a hole through the floor of a neighbor he thought was being too loud.

Currently law enforcement agencies are trying to figure out why Alexis decided to go on a shooting rampage. He may have had a problem with his treatment by the Navy, though he did receive an honorable discharge at his request in 2011, despite numerous black marks on his record. CNN reports that he may have been angry over payment issues regarding a recent work stint in Japan.

Authorities have released the names of the following victims:

  • Michael Arnold, 59
  • Sylvia Frasier, 53
  • Kathy Gaarde, 62
  • John Roger Johnson, 73
  • Frank Kohler, 50
  • Kenneth Bernard Proctor, 46
  • Vishnu Pandit, 61

The five remaining victims' families are still being contacted, which is why their names are still unavailable.

Three people who were shot but survived are safe and doing well now. A D.C. police officer who was shot in the legs and a civilian woman who was shot in the shoulder remain in the hospital in fair condition. Another civilian whose head was grazed by a bullet is in good condition and will likely go home soon.

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