As he carried out the worst mass-shooting in U.S. history Sunday morning, Omar Mateen checked Facebook to see if he was trending.
During his three-hour assault on Pulse, a popular gay nightclub in Orlando, Mateen paused to search “Pulse Orlando” and “shooting.” He also used the social media platform that morning to pledge allegiance to the Islamic State, although the timing of his posts is less clear.
“In the next few days you will see attacks from the Islamic state in the usa,” he wrote in his final Facebook salvo.
Mateen’s activity on Facebook as he plotted and carried out a shooting that killed 49 and wounded 53 added new, chilling details to the Sunday morning massacre at Pulse. His activity was detailed by U.S. Sen. Ron Johnson, R-Wisconsin, in a letter to Facebook founder Mark Zuckerberg.
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Johnson wrote to Zuckerberg Wednesday to ask him to assist the committee’s inquiry into the terrorist attack.
“I ask that you please provide all Facebook data on Mr. Mateen’s activities on his account and any affiliated Facebook accounts, including but not limited to activity logs, Facebook timeline information, Facebook messages, photos and posts,” wrote Johnson.
Johnson clarified that Facebook isn’t a target of any inquiry, but asked for the information, and for Facebook officials to attend a briefing with committee staff, no later than June 29. A Facebook spokeswoman declined to comment.
Authorities and witnesses say Mateen opened fire with a Sig Sauer MCX rifle and Glock 17 pistol inside Pulse right around last call at 2 a.m. He spent about three hours inside the club with the dead, wounded and trapped before police finally burst into the club and killed him around 5 a.m.
Police had already stated that Mateen pledged allegiance to ISIS during a call with authorities from inside the club, and local station News 13 said he also called the station and made a statement about ISIS.
Mateen was likely inspired by Islamic extremism, according to the FBI and President Barack Obama, who went to Orlando Thursday. But there’s no signs he acted on orders from anyone abroad. And his motives may be more complicated: several club-goers said Mateen frequented Pulse for months, and was gay himself.
According to Johnson, Mateen had at least five associated Facebook accounts, and on Sunday morning posted “America and Russia stop bombing the Islamic state ... I pledge my allegiance to abu bakr al Baghdadi...may Allah accept me.”
He also condemned “the filthy ways of the west,” and U.S. airstrikes that kill “innocent women and children.”
“Now taste the Islamic state vengeance,” Mateen wrote, according to Johnson.
A source with knowledge of the ongoing investigation said Mateen posted this last statement just minutes before the shooting began.
Johnson also said his staff learned that Mateen searched for information on the San Bernardino, California, shooters in May, and searched for “Baghdadi Speech” on June 4. They also learned that Mateen frequently used Facebook to search for information on the FBI and local law enforcement agencies.
In another development Thursday, the co-owner of a Jensen Beach gun shop told the Palm Beach Post that his employees last month reported a suspicious interaction with a man to the FBI after the customer tried to buy body armor and bulk assault rifle ammunition. They didn’t know it at the time, but that man turned out to be Mateen.
The Post reported that Robert Abell, co-owner of Lotus Gunworks, said Mateen came to his shop wanting body armor, and placed a call in a foreign language after being told the shop didn’t carry the equipment. When Mateen got off the phone, Abell said he asked for bulk ammunition for semi-automatic rifles, which the store declined to sell to him.
Abell told the Post that federal investigators later called his shop, but didn’t pull any surveillance footage. It wasn’t until after Sunday morning’s shooting that Abell’s employees recognized that they’d had Mateen in their store.
An employee who answered the phone at the gun store Thursday afternoon declined to comment.
Miami Herald staff writer Nicholas Nehamas contributed to this report.