By Audrey Ash, Thomas Bordeaux, Brynn Gingras, Yahya Abou-Ghazala, Curt Devine, Jeff Winter, Casey Tolan, CNN
(CNN) — The attackers who killed three people Monday at a San Diego mosque shared a live video of the shooting as well as a lengthy written document citing racist, Islamophobic and antisemitic ideology.
The graphic video, which CNN reviewed, appears to capture the attackers firing weapons from inside the mosque while displaying Nazi and white supremacist imagery on their weapons and clothing. Another portion of the video appears to show one gunman shooting the other inside a car and then shooting himself.
One attacker was identified by authorities as 17-year-old Cain Clark; the other, an 18-year-old male, has not yet been publicly identified.
The video and a 75-page hate-filled screed apparently written by the gunmen were obtained by researchers at the Institute for Strategic Dialogue, which studies extremism, and provided to CNN. A law enforcement source with knowledge of the case, who requested anonymity to discuss an ongoing investigation, confirmed to CNN that the video is believed to be legitimate and that investigators are reviewing the writings.
At a news conference, Mark Remily, the special agent in charge of the FBI San Diego office, said investigators had recovered a written “manifesto” and were analyzing it. It’s not clear whether the document is the same as the one reviewed by CNN.
The ISD researchers told CNN they believed the document is legitimate because the content lines up with what is shown in the livestream video and it references usernames matching social media accounts that posted similar ideology before the shooting.
One clip reviewed by CNN from the livestream video shows the gunmen in the parking lot of the Islamic Center of San Diego, the region’s largest mosque. They are seen entering the building’s front doors holding rifles and at least one pistol.
At least one of the men then appears to fire his weapon through the building’s doors to the exterior of the Islamic center. They walk around inside the building, while one seems to adjust his rifle. CNN matched details in the video to the Islamic center, including the entrance and interior.
The video shows them walking outside, where one fires a pistol. The video also shows an apparent victim lying on the ground in a pool of blood. The clip ends as the two gunmen enter a vehicle.
A second clip starts later and appears to show the men driving in a car.
The passenger records the video as a gun is fired through the car window. The passenger says something directly to the camera, although the video lacks any audio.
The driver pulls the car over, and then apparently fires at the passenger. The driver then shoots himself in the head.
CNN geolocated the final moment of the video to a neighborhood just south of the mosque where police recovered the vehicle and where the gunmen were found dead.
The guns seen in the video are black with hand-written white lettering and symbols drawn on them. The writing includes numerical codes and abbreviations that reference Nazism, as well as messages about past mass shootings.
The ideologies referenced by those symbols are expressed more explicitly in the document apparently signed by the two gunmen.
The document includes two separate statements attributed to each gunman expressing support for white supremacist ideology, including specifically referencing the racist “Great Replacement” conspiracy theory that white populations are deliberately being replaced. They also describe admiration for previous mass shooters, and repeatedly endorse nihilistic and antisemitic ideas.
In the statement attributed to Clark, the author writes extensively about his hatred for non-white and non-Christian cultures. The message attributed to the other gunman lauds Adolf Hi