The FBI released surveillance video Wednesday of Aaron Alexis's attack on the Washington Navy Yard.
The footage first shows Alexis driving a car into a garage. Then, he is seen entering the Naval Sea Systems Headquarters from outside with a backpack.
With badges attached to his clothes, Alexis is then shown carrying a long gun in a hallway.
Alexis hides behind a wall, watching them exit, and then heads toward them with gun in hand. The video ends there.
White House press secretary Jay Carney said Wednesday that "every American" should watch the video to remind themselves of the horror of mass shootings.
"Every American should look at that and agree with those who say, including the chief medical officer at that hospital, that this should not be acceptable to us," Carney said. "We should not be numb to that reality, and we should be doing something about it."
The White House spokesman said President Obama "continues to call on Congress" to pass a gun control bill that would expand background checks.
"He feels as strongly about that today as he did earlier this year when the Senate, in one of its least noble acts, defeated that bill," Carney said.
Police say Alexis shot and killed 12 people and wounded four others before being killed by police during the Navy Yard attack.
The FBI is still seeking information about Alexis, who died at the scene Sept. 16.
FBI officials on Wednesday shared the following timeline of the events the morning of the attack:
- 7:53 a.m. - Alexis’s rental car, a blue Toyota Prius with New York plates, entered Parking Garage #28 at the Washington Navy Yard, located directly across from Building #197.
- 8:08 a.m. - Alexis exited Parking Garage #28 on foot carrying a backpack. Alexis entered Building #197 and proceeded to the elevator.
- 8:09 a.m. - Alexis exited the elevator on the fourth floor and entered the men’s bathroom carrying a backpack and a clipboard.
- 8:15 a.m. - Alexis crossed the hallway into the 4 West area of Building #197 with shotgun but without the backpack or a clipboard.
- 8:16 a.m. - Alexis shot the first victim in the 4 West area of Building #197.
- 8:17 a.m. - First 911 call is received from the fourth floor of Building #197.
- 8:20 a.m. - Alexis left the fourth floor using the stairs and entered the third floor.
- 8:28 a.m. - Alexis appeared on the first floor.
- 8:57 a.m. - Alexis returned to the third floor.
- 9:25 a.m. - Law enforcement shoot and kill Alexis on the third floor.
The FBI said Alexis arrived in the District on Aug. 25 and stayed at hotels in Bethesda, Md.; Arlington, Va.; and Southwest D.C.
Alexis began working at the Navy Yard Sept. 9 — just a week before the shooting.
The Saturday before the attack, he purchased a Remington 870 shotgun and ammunition at a gun store in Northern Virginia. That same day, he also bought a hacksaw at a home improvement store, according to the FBI.
During the course of the shooting, he obtained a Beretta handgun. Law enforcement recovered both weapons at the scene; they are currently being analyzed by FBI forensic analysts.
Confirming previous reports, the FBI said phrases were etched into his shotgun including “End to the torment!” “Not what yall say!” “Better off this way!” and “My ELF weapon!”
The last one, the FBI says, indicates Alexis did experience “delusional” beliefs that he was being controlled by extremely low frequency (ELF) electromagnetic waves.
Alexis served in the Navy from 2007 to 2011. After his discharge, he applied to receive disability benefits from the Department of Veterans Affairs — none of which covered mental health issues. There are, however, more recent incidents that suggest he did have such problems.
To date, the FBI has determined Alexis acted alone.