'Chilling': FBI releases surveillance video footage of Navy Yard shooter Aaron Alexis

The FBI released video today of Aaron Alexis, gun in tow, at the Washington Navy Yard prior to the shooting that left a dozen people dead:

https://twitter.com/Matthops82/status/382926867453329408

Absolutely frightening.

FBI just released video of shooter Aaron Alexis in Navy Yard. Chilling, eerie, all similar adjectives: http://t.co/RbyihiyhrD

— Andrew Katz (@katz) September 25, 2013

https://twitter.com/ndiblasio/status/382929024013451264

The video becomes even more terrifying when you think about what happened next.

https://twitter.com/BrentinOcker/status/382928143046443008

Damn, the FBI just released video of Aaron Alexis during the Navy Yard shooting in DC. It's harrowing, I feel for the victims' families. 🙁

— Neale (@AbeFroman) September 25, 2013