Aaron Alexis believed he was being controlled by electronic waves and likely acted alone in his deadly shooting spree at the Washington Navy Yard, according to new details released by the FBI on Wednesday.
This new information also includes chilling security camera video footage of the gunman stalking through the hallways of Building #197 with a loaded shotgun.
Valerie Parlave, the assistant director in charge of the FBI's Washington Field Office, held a press conference Wednesday alongside other security officials associated with the case. Alexis did not appear to target any particular people in his Sept. 16 rampage, she said, that resulted in 12 killings, as well as his own death.
Alexis, a contractor for a private information technology firm, arrived in Washington Aug. 25, according to the new FBI details. He stayed at a hotel in Bethesda, Md. until Aug. 31, when he moved to a hotel in Pentagon City, just across the Potomac River from the Navy Yard and adjacent to the Pentagon in Arlington, Va.
On Sept. 7, he moved to a Residence Inn in Southwest D.C. where he remained through Monday, Sept. 16., the date of the shooting.
The Saturday before, he bought a Remington 870 shotgun and ammunition for it at a gun shop in Virginia. He also purchased a hacksaw at a home improvement store, which he could have used to saw off part of the shotgun's barrel.
The shotgun was also rudimentarily engraved with phrases such as "Not what yall say!" and "Better off this way!" It also included "My ELF weapon," which FBI believes references extremely low frequency electromagnetic waves. There are conspiracy theories suggesting these frequencies, used by submarines, can also be used for mind control, said Parlave.
Alexis also wrote in an electronic document recovered by the FBI, "Ultra low frequency attack is what I've been subject to for the last 3 months, and to be perfectly honest that is what has driven me to this."
The FBI released details of Alexis' activities during the shooting. A full timeline is available below.
Parlave also confirmed earlier reports that Alexis had a valid security clearance and entered the Navy Yard using a security pass.
The details of Alexis' troubled past, and his ability to still attain a security clearance "certainly jumped out at me," said Ash Carter, the deputy secretary of defense, while speaking with reporters on Wednesday about the Pentagon's planned reviews of the shooting.
"Had it been spotted and understood to be indicative of this possibility, [it] might have led to an intervention," said Carter.
Defense Secretary Chuck Hagel announced Sept. 18 that both the Pentagon and the Department of the Navy would conduct reviews of the security at military installations, and the process by which personnel are issued security clearances. A third review will be conducted by an independent panel.
Carter announced Wednesday that panel will be headed up by Paul Stockton, the assistant secretary of defense for Homeland Defense and Americas' Security Affairs, and retired Navy Adm. Eric T. Olson, a former SEAL who served as chief of U.S. Special Operations Command from 2007 to 2011.
The Pentagon's review will be led by Mike Vickers, the undersecretary of Defense for Intelligence, himself a former CIA paramilitary officer and Army Special Forces soldier.
The Navy's review must be completed by November, and a full report from the Defense review must be submitted to Hagel by Dec. 20.