Orlando Shooter on Facebook: Now 'Taste' ISIS 'Vengeance'

— -- The same morning Omar Mateen killed 49 people at a gay nightclub in Orlando, he posted on Facebook his allegiance to ISIS, demanded that the U.S. and Russia to “stop bombing” the terrorist group and warned of attacks to come, FBI officials said.

“You kill innocent women and children by doing us airstrikes..now taste the Islamic state vengeance,” Mateen posted early Sunday morning, according to officials in the FBI’s counterterrorism division. “In the next few days you will see attacks from the Islamic State in the usa.”

Information about the posting circulated among law enforcement agencies Tuesday morning. The officials also said four Facebook accounts have been found to be associated with Mateen.

In May he searched on Facebook for the couple behind the February attack in San Bernardino, California. Late Tuesday, officials said they were investigating whether Mateen’s wife, 30-year-old Noor Mateen, knew about or had anything to do with the Orlando plot.

The FBI officials also said that in the days leading up to the attack, Omar Mateen searched online for a speech by ISIS leader Abu Bakr al-Baghdadi, for information about the gun store where he legally purchased a handgun and semiautomatic rifle used in the shooting and for the Pulse nightclub. He previously searched several times for local law enforcement offices.

ABC News local affiliate WFTV reported on portions of the Facebook posting and the searches Tuesday. FBI Special Agent Ron Hopper declined to comment on the Facebook pages today, telling reporters that the FBI’s “digital analysis is ongoing.”

Today a different local TV channel revealed that Mateen called the station and spoke with one of its producers, apparently during the attack, and said, “I’m the shooter. It’s me.”

“He did it for ISIS,” producer Matt Gentili said, according to Orlando’s News13. He asked the caller to identify himself and got the reply, Gentili said, that it was “none of my [expletive] business.”

Mateen called 911 to declare his allegiance to ISIS after the shooting began, officials said.

Also today, video footage emerged of a disgruntled Mateen working as a security guard in 2010, in “The Big Fix,” a documentary about the BP oil spill.

“No one gives a [expletive] here,” he tells an undercover reporter. “Like, everybody’s just out to get paid. They’re, like, hoping for more oil to come out and more people to complain so they’ll have a job.”

A Double Life?

While ISIS has praised the attack and claimed Mateen as one of its “soldiers,” terrorism experts have told ABC News that so far, there is no evidence that ISIS had foreknowledge of or played any significant role in the plot, beyond perhaps generally inspiring him to act.

The FBI is reportedly investigating what effect, if any, Mateen’s sexuality may have played in the targeting of the popular gay nightclub.

Mateen was an observant Muslim, and his ex-wife said he was openly derogatory about gay men, but in recent days witnesses have come forward to say he was a regular at gay nightclubs in Florida.

His interest in gay men goes back as far as a decade, according to a former classmate of Mateen’s at a police academy, who told ABC News that Mateen hung out with a group that frequented gay clubs.

The classmate said that one night Mateen asked him if he was gay. “You would be my kind of guy,” Mateen said, according to the classmate.

Mateen’s ex-wife, Sitora Yusufiy, told ABC News on Monday that he would become enraged and “express his anger towards [a] certain culture, homosexuality, because in ... Islamic culture, it is really not tolerated, and I know at the time he was trying to get his life straight and follow his faith.”

“I guess that created some confusion between that, and there was definitely moments that he would express his intolerance to homosexuals,” said Yusufiy, who left Mateen just a few months after they were married in 2009.

The next day, she said that, looking back, “I think he might have been” gay.

“You know, knowing somebody and living with them every day ... I can honestly say that I had no clue,” Yusufiy told ABC News on Tuesday. “But from everything that has occurred and connecting the pieces to what I knew myself from my time and experience, I would not be surprised.”

Cases in which repressed homosexuality has been linked to extremism have been an interest for counterterrorism officials. In 2011 an analysis of homegrown extremists by the National Counterterrorism Center and obtained by ABC News included a secret report from the CIA that said that for some young men who converted to Islam and later became radicals, the strict religious structure offered “a hope of banishing their impulses and fantasies that they did not view as acceptable.”

Jerrold Post, formerly a longtime psychologist with the CIA, told ABC News on Tuesday that over his career, he has seen the psychodynamic of individuals “striking out against a forbidden part of oneself” but that at this point, it’s too early to leap to conclusions about Mateen’s motives.

“Is this an expression of radical Islam? Or does it have to do with the conflicted feelings about homosexuality?” said Post, now a professor of psychology at the Elliot School of International Affairs at George Washington University. “That’s an unnecessary separation. One can be, on the one hand, fighting against the perhaps inner attraction of homosexuality and at the same time honoring the act by saying he was a radical Islamist. It doesn’t have to be one or the other. But at this point, it’s all speculation.”