Further details about 29-year-old Orlando nightclub shooter, Omar Mateen, are emerging as police continue to investigate the attack that left 49 dead and 53 injured.

QUESTIONS ABOUT SEXUALITY

In an interview with The Associated Press late Monday, Jim Van Horn spoke to reporters about Mateen, who he claimed was a 鈥渞egular鈥 at Pulse nightclub who would try to pick up men.

Van Horn, who lost three friends in the shooting, says he met Mateen once and the two talked about the latter鈥檚 ex-wife, before friends pulled the 71-year-old away because "they thought [Mateen] was a strange person."

Ty Smith, a Pulse patron, also told the Orlando Sentinel that he saw Mateen inside the nightclub at least a dozen times, recalling, "sometimes he would go over in the corner and sit and drink by himself, and other times he would get so drunk he was loud and belligerent.鈥

Questions are now being raised about Mateen鈥檚 sexuality as a possible factor in the attack. Reports claim he may have been on the popular gay dating app Grindr.

One man, Kevin West, claims Mateen contacted him via the app in an interview with an ABC station.

鈥淲hen he first contacted me, he was saying, like asking, what clubs, in his words, what clubs are popping and things of that sort, and what are good places are to go,鈥 says West.

WHAT HIS FATHER SAID

Mateen鈥檚 father Seddique Mateen has speculated that his son鈥檚 anti-gay hatred could have been a catalyst for the violence, saying his son became enraged after seeing two men kissing in Miami.

He told ABC News Tuesday that they were at a concert together when they saw two men kissed and his son 鈥渨as kind of shocked鈥 and that he 鈥渏ust didn鈥檛 want it.鈥

He also said his son briefly visited him on Saturday afternoon, and that he didn鈥檛 notice anything strange. 鈥淚 would have called the law enforcement,鈥 he said. 鈥淚 would have been so happy (if) they would (have taken) him away. I wish. I wish.鈥

鈥淚t鈥檚 a very sad day for everyone,鈥 Mateen added. 鈥淓specially for me as a father. When you鈥檙e a father 鈥 you have high expectations from your son.鈥

鈥淚 had only one son and all of us in the past three days, the whole life of everybody got changed,鈥 he went on. 鈥淓specially us.鈥

In a video posted to his Facebook profile on Monday, Seddique said, "God himself will give punishment to homosexuality.鈥 The video has since been deleted.

TERRORIST TIES?

On Monday FBI Director James Comey confirmed Mateen spoke with 911 operators three times during the shooting rampage on Sunday morning.

At one point he called Boston marathon bombers Dzhokhar and Tamerlan Tsarnaev his "homeboys,鈥 claimed solidarity with a suicide bomber from Nusra Front (a Syrian rebel group and an enemy of ISIS) and in the last call he pledged allegiance to ISIS.

Also on Monday, Islamic State鈥檚 official radio station al-Bayan released a bulletin in which they described the Mateen as 鈥渁 soldier of the Caliphate in America,鈥 according to a translation from Reuters.

Records show Mateen also made claims of family ties to al Qaeda and that he was a member of Hezbollah, which happens to be an enemy organization to ISIS.

Comey confirmed the FBI is looking into reports that Mateen may have scouted other locations, including Walt Disney World, but wouldn't comment further.

"We are going through the killer's life, as I said, especially his electronics, to understand as much as we can about his path and whether there were anyone else involved either in directing him or in assisting him," says Comey Tuesday.

UNDER INVESTIGATION

The FBI had interviewed Mateen three times prior to the shooting, including as recently as 2014.

The Bureau opened a file on him in 2013, after concerns were registered about allegedly extremist comments Mateen made to co-workers. He was interviewed twice during a 10-month investigation that included surveillance and a review of his communications, but the file was closed with Mateen claiming he only made the threats because co-workers were teasing him.

FBI spokesperson James Comey says Mateen also told coworkers "he hoped that law enforcement would raid his apartment and assault his wife and child so that he could martyr himself.鈥

In 2014 Mateen was back in the crosshairs of the FBI for alleged ties to American suicide bomber Moner Abu Salha. They determined contact was "minimal" and did not constitute "a threat at that time."

Mateen was not under surveillance at the time of the nightclub shooting.

CONFLICT WITH COWORKERS

Co-workers have also been providing insight into Mateen, with some of them describing him as an angry, threatening and homophobic man.

"He talked about killing people all the time," Daniel Gilroy, a former co-worker of Mateen's at G4S, told The New York Times. Gilroy eventually reported Mateen's behaviour to his bosses, but, according to him, not much was done.

"I kind of feel a little guilty that I didn't fight harder," Gilroy said. "If I didn't walk away and I fought, then maybe 50 people would still be alive today. I saw it coming."

BORN AND RAISED IN AMERICA

Court documents reveal Mateen was born in Queens, New York to Afghani immigrant parents and moved to Port St. Lucie, Fla., in 1991. He graduated from Indian River Community College in 2006. On Monday the Saudi government confirmed Mateen visited the kingdom twice between 2011 and 2012 to perform an Islamic pilgrimage to Mecca.

Between 2001 and 2006, he worked at eight jobs, including at a Publix grocery store, Circuit City, Chick-Fil-A, Walgreens, Nutrition World, Gold's Gym and GNC.

His employment history was included as part of a submission to petition, shortly after his college graduation, to legally change his name from Omar Mir Seddique to Omar Mir Seddique Mateen. There was no reason provided for the name change.

At the time of his death, Mateen was a licensed security guard and a father of a three-year-old boy. He spoke English and Farsi fluently.

RELIGIOUS, NOT RADICAL

Syed Shafeeq Rahman, the imam at the mosque Mateen attended in St. Pierce, has known him since he was a child. He describes Mateen as a serious, quiet and regular worshipper who never exhibited any signs of violence.

"When he finished prayer he would just leave," Rahman told The Associated Press. "He would not socialize with anybody. He would be quiet. He would be very peaceful."

ABUSIVE MARRIAGE

Sitora Yusufiy, the ex-wife of the shooter, talked to reporters in Boulder, CO., on Sunday, and painted a different picture.

During the conference Yusufiy, who was married to Mateen for four months in 2009, called her ex-husband "bi-polar鈥 deeply disturbed" and claims her family rescued her from the abusive relationship.

She also alleged her ex-husband abused steroids, which exacerbated his "emotional instability" during their marriage.

Despite this, Yusufiy says she never suspected Mateen 鈥 who aspired to be a police officer 鈥 was capable of such violence.

Mateen was remarried with one child at the time of the shooting.

His current wife, Noor Salman, may face criminal charges for failing to report her husband to authorities after she revealed he told her of his plan, according to NBC.

Salman also admitted she was with Mateen when he purchased ammunition and a gun holster. She also drove him to the club once so he could scout the location.

LEGALLY ALLOWED TO CARRY

Because of his security guard licence from his job with U.K.-based security firm G4S, Mateen was registered to carry a firearm and was able to legally buy the guns he used in the attack in Florida.

The company also said that, in order for Mateen to get clearance to work for them, he had to go through rigorous background checks conducted by the U.S. government. No findings were reported in those searches the most recent of which was in 2013.

Police say Mateen used a semi-automatic Sig Sauer MCX military-style rifle and a 9mm Glock pistol and unknown amount of ammunition in the shooting.

A spokesman for The Bureau of Alcohol, Tobacco and Firearms confirmed the weapons were purchased in the last week or so.

American law does not prohibit selling firearms to people suspected of terrorism.

Mateen had no other criminal record.

With files from The Associated Press