The FBI released more details about last week’s shocking shooting at Navy Yard to the public. A new video surfaced this afternoon that shows the shooter Aaron Alexis entering the facility and stalking the hallways with a shotgun in the seconds before he went on a violent shooting that left 12 people dead. He himself was eventually put down by authorities.

Victims were chosen at random, the FBI confirmed. Photographs of the shotgun with writing etched in the side and his backpack left behind in a bathroom stall were also released.

See the video below.

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SOURCE: FBI