The FBI shared details Wednesday of its investigation into the shooting at the Washington Navy Yard which occurred on Sept. 16.

Though the investigation is not yet complete, the information is intended to update the public with details of the incident and potential motives for the crime. The FBI's release includes a statement explaining what the department has discovered thus far about suspected shooter Aaron Alexis, in addition to a video and 12 photos.

"There are multiple indicators that Alexis held a delusional belief that he was being controlled or influenced by extremely low frequency (ELF) electromagnetic waves," reads the FBI's statement.

The agency noted that Alexis used two weapons — a Remington 870 shotgun and a Beretta handgun — during the attack. Among several phrases etched onto the shotgun was one that reads, "My ELF weapon." The FBI further explained the significance of ELF in the following quotation and in the video below:

ELF technology was a legitimate program for naval sub-tonal submarine communications; however, conspiracy theories exist which misinterpret its application as the weaponization of remote neural frequencies for government monitoring and manipulation of unsuspecting citizens.

The photos show additional phrases etched into the weapon, including "End to the torment," "Not what yall say," and "Better off this way."

Twelve people died during the attack on the Naval Sea Systems Command Headquarters Building, which a Navy spokesperson described as an administrative building.

The FBI statement lists a sequence of events, beginning with Alexis entering a parking garage in a blue Toyota Prius at 7:53 a.m. and ending at 9:25 a.m., when law enforcement officials shot and killed him.

The FBI also released video footage which strings together the events it lists. There is no indication Alexis was targeting specific individuals during the attack, according to the Bureau.

Below are some of the images the FBI released, which include a security camera photo of an armed Alexis. More images and video footage are available on the FBI's website.

FBI Photos of the Navy Yard Shooting

Images: Drew Angerer/Getty Images