Omar Mir Seddique Mateen has been named as the gunman who killed 49 people and wounded 53 others at the Pulse nightclub in Orlando, Florida, CBS News reports.

The gunman was later killed by police after taking hostages at the LGBT club. The shooting, carried out with an AR-15 rifle and a handgun, is the deadliest in American history.

He pledged allegiance to ISIS, the so-called Islamic State, before the shooting, according to Congressman Adam Schiff, D-California.

Mateen, 29, is a U.S. citizen of Afghan descent from Port St. Lucie, Florida, according to CBS News. He has ties to radical Islamic ideology, CBS reports. His name was confirmed by Congressman Alan Grayson at a press conference.

Port St. Lucie is about 125 miles away from Orlando.

Police have not yet said why Mateen attacked the Pulse club. His father told MSNBC that the shooting was not about his son’s religion, but that his son became very angry after seeing two men kissing in Miami months ago. He said “we are apologizing for the whole incident.”

“We are saying we are apologizing for the whole incident. We weren’t aware of any action he is taking. We are in shock like the whole country,” Mir Seddique, his father, told NBC News.

But on Monday, a day after the shooting, a former classmate and other acquaintances told several media outlets that Mateen may have been gay. The former classmate at a community college told the Palm Beach Post that Mateen once asked him out. Others who knew him said he frequented the Pulse nightclub for several years before the shooting and also used gay dating apps.

Mateen’s father told the Post that his son is not gay.

Click here for the names of the victims as they are identified.

Here’s what you need to know about Mateen:

1. Mateen Called 911 & Pledged His Allegiance to the ISIS Leader

Omar Mateen called 911 just before the shooting and pledged allegiance to ISIS leader Abu Bakr al-Baghdadi, NBC News reports.

He also mentioned the Tsarnaev brothers, who carried out the Boston Marathon bombing, during the call, CBS News reports.

ISIS issued a statement calling Mateen an “Islamic state fighter.” Read the full statement here.

Congressman Adam Schiff, a California Democrat, said in a press release that the attack appears to be an “ISIS-inspired act of terrorism.”

He said Mateen declared his allegiance to ISIS before the assault, according to local law enforcement. Schiff is the ranking member on the House Permanent Select Committee on Intelligence and said he received a preliminary briefing on the attack.

“This attack is so painfully reminiscent of the terrible attack at the Batlaclan Theatre in Paris, and other ISIS-inspired attacks in recent years,” Schiff said. “The fact that this shooting took place during Ramadan and that ISIS leadership in Raqqa has been urging attacks during this time, that the target was an LGBT night club during Pride … Whether this attack was also ISIS-directed, remains to be determined.”

The FBI has not confirmed Schiff’s statement.

Local FBI Assistant Special Agent-in-Charge Ron Hopper said at a press conference that there are “suggestions” the gunman “may have leanings” toward Jihadist ideology. Hopper had been asked about whether the shooter was connected to radical Islamic terrorism.

Hopper said they can’t say definitively whether the gunmen is connected to that ideology. He said we’re looking into all angles right now.”

Police were searching Mateen’s home in Port St. Lucie on Sunday morning:

FBI and PSLPD now on scene at Port St. Lucie home listed for 29-year-old Omar Mateen – @GabrielleSarann pic.twitter.com/89HLvqZNPM — WPTV (@WPTV) June 12, 2016

Mateen has no known criminal history, according to CBS News.

But The Daily Beast, citing a senior law enforcement source, said Mateen was a person of interest in law enforcement investigations in 2013 and 2014. The news website reports the FBI opened an investigation into Mateen at some point, but closed it “when it produced nothing that appeared to warrant further investigation.”

Law enforcement at the parents home in Port St. Lucie of Saturday's Orlando shooter Omar Mateen, of Fort Pierce. pic.twitter.com/5oL81hWeDb — Eric Hasert (@TCPalmHasert) June 12, 2016

The source told The Daily Beast he’s a “known quantity” who has “been on the radar before.”

The FBI later confirmed during a press conference that Mateen was interviewed by agents twice in 2013 after he made suspicious comments about radical Jihadism that were heard by coworkers. He was interviewed a third time, in 2014, based on his connection to Moner Mohammad Abu Salha, an American from Florida who trained in Syria, traveled back to his home state and tried to recruit other Americans, and then went back to Syria, where he blew himself up in a suicide bombing.

There were no open investigations and Mateen was not under surveillance at the time of the shooting, the FBI said.

CNN reports that Mateen was a known ISIS sympathizer.

The shooting happened during the Muslim holy month of Ramadan, a time during ISIS has instructed its supporters to carry out terror attacks around the world, according to CNN.

A speech on May 21 by ISIS spokesman Abu Muhammad al Adnani, “That They Live By Proof,” called for attacks in the West. You can read the speech here and listen here.

ISIS supporters and sympathizers on Twitter posted messages after the shooting, but there have been no official claims by the Islamic State terror organization.

Later Sunday, a man was arrested in Santa Monica, California, with assault weapons, possible explosives, a security badge and camouflage, the Los Angeles Times reports. The man, James Howell, 20, of Indiana told police he was in town for the West Hollywood gay pride parade and wanted to cause “harm” there. Police said there is no evidence the incidents are connected or that Howell has ties to terrorism.

Read more about that arrest at the link below:

See more photos of Mateen at the link below:

Read more about Omar Mateen in Spanish at AhoraMismo.com:

2. He Was a Security Officer With a Gun License Whose Father Once Tried to Run for the Afghan Presidency & Supported the Taliban

Both of Mateen’s parents are originally from Afghanistan, according to CBS News.

Mateen was born in New York. His father, Seddique Mateen, who has also been called Mir Seddique, once tried to run for the Afghan presidency and was heavily involved in politics, according to his Facbeook page, which includes photos inside a U.S. State Department office. He has also spoken out against the Pakistani government, and supported the Taliban.

“Our brothers in Waziristan, our warrior brothers in Taliban movement and national Afghan Taliban are rising up,” he said in one YouTube video, according to the Washington Post. “Inshallah the Durand Line issue will be solved soon.”

Seddique Mateen candidacy announcement for President of Afghanistan_B (5.23.2015 Part 3 of 3)Durand Jirga Show – Seddique Mateen candidacy announcement for President of Afghanistan & end of intelligent agreement_B (5.23.2015 Part 3 of 3) 2015-05-25T00:10:29.000Z

You can read more about Mateen’s father here.

Mateen had a license to be a security officer and a firearms license in Florida, according to the state records.

He worked for G4S Secure Solutions, a Jupiter-based security company, since 2007

“We are cooperating fully with all law enforcement authorities, including the FBI, as they conduct their investigation,” the company said in a statement. “Our thoughts and prayers are with all of the friends, families and people affected by this unspeakable tragedy.”

A co-worker at G4S, Daniel Gilroy, told Florida Today he worked the 7 a.m. to 3 p.m. shift at PGA Village in Port St. Lucie. Gilroy, a former police officer, said Mateen would then take over from 3 p.m. to 11 p.m.

Gilroy told the newspaper that Mateen “stalked” him, sending up to 15 messages a day and made racist and homophobic comments.

“I quit because everything he said was toxic,” Gilroy said, “and the company wouldn’t do anything. This guy was unhinged and unstable. He talked of killing people.”

Mateen purchased two weapons, a Glock handgun an an AR-15 rifle, in the days before the shooting, the federal Bureau of Alcohol, Tobacco, Firearms and Explosives said at a press conference. The ATF did not detail where the guns were purchased and did not say if those weapons were used in the Orlando shooting.

U.S. Rep. Peter King, of New York, told CNN that the gunman was “trained in the use of weapons.”

He worked as a security officer in Port St. Lucie and had a criminal justice degree from a local college. He is pictured wearing NYPD shirts in multiple photos on MySpace, but the NYPD told TMZ that Mateen had no affiliation to the department. The souvenir shirts could be bought at several stores, the NYPD said.

But his ex-wife said he wanted to be a police officer and applied for the police academy, Reuters reports.

The FBI says the gunman was “organized and well-prepared.” Police have not released further details about the plot or whether anyone else was involved.

Police have asked anyone with information about the shooting and the gunman to come forward.

“If you have some information, no matter how small you think it may be, that would relate back to today’s events, please share it with us,” Hopper said. “I would urge you to call the 1-800-CALL-FBI public access line, we have phones standing by to take any information or lead whatsoever.”

Hopper said they will be conducting interviews and a huge FBI presence will be seen in coming days.

A man who answered the phone at Mateen’s home, Mustafa Abasin, told NBC News “we are in shock and we are sad,” but didn’t say how he knew Mateen. He said he is helping investigators.

The shooting comes one night after former Voice contestant Christina Grimmie was gunned down outside of Plaza Live, about four miles away from Pulse. The gunman in that shooting, Kevin Loibl, fatally shot himself, police said.

But police said the shootings are not connected.

3. His Ex-Wife Says Mateen Beat Her & She Was Rescued From Their Marriage After Only a Few Months

Mateen was married in 2009 to woman from New Jersey, Sitora Yusufiy, public records show. They divorced in 2011. Yusufiy told Heavy.com that she was rescued from the relationship by her family after just a few months, but the divorce took several years to be formally completed.

http://heavy.com/news/2016/06/omar-mateen-wife-married-divorce-sitora-yusufiy-isis-facebook-page/

Yusufiy told the Washington Post Mateen was abusive.

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

She said they met online and he “seemed like a normal human being,” but was “very private.” She said he wasn’t very religious and worked as a guard at a facility for juvenile delinquents.

But when he became abusive, her father flew down to Florida and pulled her out of the house. She said her parents saved her life.

Mateen had a 3-year-old son with his second wife, Noor Zahi Salman, 30. He has been married to her since at least 2013, according to public records.

His father said that Mateen was angered because he saw two men kissing in front of his young son, NBC News reports.

Mateen is a registered Democrat who has also lived in Fort Pierce, Florida, according to online records.

He was also a notary public in Florida, but his license, issued in 2008, expired in 2012, records show.

4. He Exchanged Fire With a Police Officer Outside the Club Before Going Inside & Taking Hostages

The gunman, Omar Mateen, was engaged in a shootout with police outside the night club at about 2 a.m., police said at a press conference. Mateen then entered the night club and took hostages.

“The officer engaged in a gun battle with that suspect. The suspect at some point went back inside the club and more shots were fired. This did turn into a hostage situation,” Orlando Police Chief John Mina said at a press conference.

Mateen was armed with an “assault-type” rifle, a handgun and a “suspicious device,” authorities said.

Management at Pulse took to Facebook to warn people to stay away. Everyone is being asked to stay out of the area.

The attack occurred during Latin Night at Pulse, the one of the largest gay clubs in Orlando.

Kenya Michaels was scheduled to perform at midnight and the shooting took place around 2 a.m. Michaels’ colleagues, who were also at Pulse, are OK, according to posts that were making the rounds on social media. Roxy Andrews posted on Facebook that she was in Tampa and was fine, and that Axel Andrews and Angelica Michelle Jones made it out OK.

Fans of Michaels were on Facebook, posting and requesting an update on the performer’s status. They were asking in response to her post about performing if she was safe. It was later determined that Michaels made it out safe also.

The nightclub was at full capacity when the shooting began. One person, who was at Pulse, posted on Twitter that he was just able to get out, but others were still inside when he fled.

5. He Was Killed by a SWAT Team in an Effort to Rescue Hostages

Mateen died at the scene after he was shot by police at about 5 a.m.. He had barricaded himself in the nightclub after opening fire. Witnesses reported that some of their friends were hiding in dressing rooms and bathrooms, trying to stay safe.

A video from the scene appears to show the moment the SWAT team engaged in a final gun battle with the suspect:

Authorities had been in contact with Mateen before the raid, but have not said what that communication was.

An officer was wounded during the shootout, but was saved by his Kevlar helmet, police said. More than 30 hostages were rescued from the club.

Pulse shooting: In hail of gunfire in which suspect was killed, OPD officer was hit. Kevlar helmet saved his life. pic.twitter.com/MAb0jGi7r4 — Orlando Police (@OrlandoPolice) June 12, 2016

Police said there was blood everywhere inside Pulse, and veteran SWAT officers were shaken by the scene.