Aaron Alexis used a legally purchased 12-gauge shotgun to kill 12 people at the Washington Navy Yard Monday morning and likely picked up a Glock handgun from one of his victims, according to the FBI.
FBI Assistant Director Valerie Parlave told reporters Alexis walked in to Building 197 with a Remington 870 shotgun. Alexis purchased the weapon at a Lorton, Va., gun shop, reports the Wall Street Journal .