Omar Mateen called 911, pledged support to ISIS amid mass shooting at Pulse nightclub in Orlando: FBI

Omar Mateen, identified as the gunman who killed about 50 people and injured at least 53 at a popular gay nightclub in Orlando, pledged his support for ISIS and invoked the names of the Boston marathon bombers in 911 calls made amid his attack on the crowded venue, according to the FBI.

Ronald Hopper, FBI assistant special agent in charge, in a news conference Sunday confirmed the shooter’s references to the terrorist network. An agent for the ATF said the shooter had legally purchased two guns, a handgun and a long gun, within the past week.

Hopper also said the FBI is not pursuing a second suspect at this time.

President Obama called the mass shooting, “an act of terror and an act of hate” in remarks on Sunday, and ordered flags flown at half-mast in honor of the victims.

Direct links have not yet been established between Mateen and ISIS, Hopper said, but the terror group claimed responsibility for the shooting, the most deadly mass shooting in U.S. history, through a statement on its Amaq news agency.

Mateen, 29, was born in New York. His parents are from Afghanistan. The family later moved to Florida, according to published reports and he has recently lived in Fort Pierce, Fla., in St. Lucie County, which is roughly 123 miles south of Orlando.

The investigation into this mass shooting is still developing, and much remains unknown about Mateen and the full scope of his motive in the shooting. Here is more on what we know about the shooter:

Mir Seddique, the suspected shooter’s father, told NBC News that the shooting had “nothing to do with religion.” He also said Mateen got angry when he saw two men kissing in downtown Miami a couple of months ago and that he thinks that may have been a trigger in the shooting.

“We are apologizing for the whole incident,” he told NBC News. “We weren’t aware of any action he [was] taking. We are in shock like the whole country.”

Authorities have identified the suspected gunman in Sunday's mass shooting that left at least 50 dead in Orlando as Omar Mateen. (Photo: Courtesy of WABC)
Authorities have identified the suspected gunman in Sunday’s mass shooting that left at least 50 dead in Orlando as Omar Mateen. (Photo: Courtesy of WABC)

Mateen’s ex-wife in an interview with The Washington Post, called the shooter “unstable” and reported he was physically abusive to her during their brief, months-long marriage in 2009.

“He beat me. He would just come home and start beating me up because the laundry wasn’t finished or something like that,” she told the newspaper.

Related: Slideshow: Shooting rampage at Florida nightclub >>>

Speaking to media, Florida Sen. Bill Nelson earlier said he was told by intelligence sources that “there is some connection to ISIS,” that had not yet been confirmed officially.

“Facts seem to connect this to terrorism, but we can’t say that totally yet,” he said.

CNN’s Evan Pérez said that Mateen had rented a car in Fort Pierce so that he could travel to Orlando for the attack and that he worked as a security officer.

Online records show he was a registered Democrat.

Law enforcement officials told ABC News that Mateen had been “on the radar” of U.S. authorities for a while, but that he was not the target of an investigation.

Florida Rep. Alan Grayson said Mateen was an American citizen, though he said he has several family members who aren’t.

From left, Orange County Mayor Teresa Jacobs, Orlando police chief John Mina and FBI agent Ron Hopper speak at a news conference on Sunday after a deadly shooting attack at Pulse nightclub in Orlando. (Photo: Kevin Kolczynski/Reuters)
From left, Orange County Mayor Teresa Jacobs, Orlando police chief John Mina and FBI agent Ron Hopper speak at a news conference on Sunday after a deadly shooting attack at Pulse nightclub in Orlando. (Photo: Kevin Kolczynski/Reuters)

Orlando Police Chief John Mina said at a news conference that an officer responded to gunshots outside Pulse nightclub around 2 a.m. and exchanged gunfire with the suspect. At that point, the gunman ran inside the dance club, opened fire again and took hostages, Mina said.

Officers from various law enforcement agencies throughout the region responded, and a SWAT team stormed the building in an attempt to rescue the hostages, shooting and killing the gunman, he said.

“The suspect is dead. He appeared to be carrying a rifle, an assault-type rifle, and a handgun, and had some type of [explosive] device on him. That’s what we’re doing right now. Checking the area for devices,” Mina said.

Gov. Rick Scott released a statement saying his thoughts and prayers are with the victims, their families and everyone affected by the tragedy.

“We are a strong and resilient state and we will devote every resource available to assist with the shooting in Orlando,” the statement reads. “Our state emergency operations center is also monitoring this tragic incident. I have been in constant communication with Orlando Mayor Buddy Dyer, Orange County Mayor Teresa Jacobs and state and local law enforcement this morning. I would like to also thank all the first responders who quickly came to assist and help those in need.”

Orlando Mayor Buddy Dyer said he issued a state of emergency for the city and that he had called Scott to request that they do the same at the state level.

He said they will focus on identifying the victims and notifying family members. They also set up a hotline for concerned family members: 407-246-4357.

RELATED VIDEO: