The FBI has released surveillance video and photos of the man who gunned down 12 people at the Washington Navy Yard on September 16. Officials also said the shooter, 34-year-old Aaron Alexis, believed he was being controlled by electromagnetic waves in the months before the rampage. Valerie Parlave, the FBI assistant director in charge of the Washington field office, said there were no indications that Alexis was targeting any one person in the shooting.

At a news conference, Parlave said, "We have found relevant communications on his electronic media, which referenced the delusional belief that he was being controlled or influenced by extremely low frequency electromagnetic waves for the past three months."

Reuters reports, "Surveillance video released by the FBI showed Alexis driving a rented blue Toyota Prius into a Navy Yard parking garage shortly before 8 a.m. Carrying a backpack, he then entered the Naval Sea Systems Command building, site of the shootings, through a door.

"The brief video also shows Alexis, armed with a Remington shotgun and wearing dark clothing, descending a stairway and walking along corridors in a crouch position, weapon held at the ready.

"People can be glimpsed at the end of one corridor. Alexis peeks around corners and, at one point, aims the shotgun into a room but does not fire.

"Parlave said Alexis, a government technology contractor, had in his possession the shotgun, which had a sawed-off barrel and stock, and a pistol he obtained during the shooting.

"Scratched into the shotgun were the phrases, 'End to the torment,' 'Not what y'all say,' 'Better off this way' and 'My ELF weapon,' photos released by the FBI showed. 'ELF' is believed to stand for extremely low frequency.'

"The photos also showed the backpack hanging in a bathroom stall Alexis entered before starting his rampage. He shot his first victim at 8:16 a.m. and police received the first emergency call a minute later from the fourth floor of the building, according