The murky picture of Orlando gunman Omar Mateen grew more complex Tuesday with word that the FBI is investigating whether he had been a regular at the gay dance club he attacked and had been leading a secret life as a gay man.

As victims described the bloody horror of the massacre during a riveting hospital news conference, investigators continued to gather information on the 29-year-old American-born Muslim -- and took a close look at his wife, too -- for clues to the attack that left 49 victims dead.

An official who was briefed on the progress of the case but insisted on anonymity to discuss a continuing investigation said authorities believe Mateen's wife knew about the plot ahead of time, but they are reluctant to charge her on that basis alone.

A number of possible explanations and motives for the bloodbath have emerged, with Mateen professing allegiance to the Islamic State group in a 911 call during the attack, his ex-wife saying he was mentally ill, and his father suggesting he was driven by hatred of gays.

On Tuesday, a U.S. official said the FBI is looking into a flurry of news reports quoting patrons of the Pulse as saying that Mateen frequented the nightspot and reached out to men on gay dating apps. The official was not authorized to discuss the investigation and spoke on condition of anonymity.

Some psychologists raised the possibility that Mateen was sexually conflicted and that those feelings might have contributed to his lashing out against gays.

Jim Van Horn, 71, told The Associated Press that he saw Mateen repeatedly at the bar and talked to him once.

"He was a homosexual and he was trying to pick up men," Van Horn said. "He would walk up to them and then he would maybe put his arm around 'em or something and maybe try to get them to dance a little bit or something."

The attack early Sunday ended with Mateen being shot to death by a SWAT team. Of the 53 people wounded, six were listed in critical condition Tuesday and five others were in guarded condition.

At a news conference at Orlando Regional Medical Center, shooting survivor Patience Carter described praying to die as she lay on a nightclub bathroom floor covered in water and blood. She said Mateen talked about wanting the U.S. to "stop bombing my country," a possible reference to his father's native Afghanistan.

"I really don't think I'm going to get out of there," Carter, 20, recalled. "I made peace with God. 'Just please take me. I don't want any more.' I was just begging God to take the soul out my body."

In Washington, President Barack Obama said investigators had no information to suggest a foreign terrorist group directed the attack. He said it was increasingly clear the killer "took in extremist information and propaganda over the internet. He appears to have been an angry, disturbed, unstable young man who became radicalized."

The president also blasted Donald Trump's anti-Muslim rhetoric as dangerous and contrary to American values, challenged Congress to reinstate the assault weapons ban, and lashed out at his Republican foes who have criticized him for not using the term "radical Islam."

"If someone seriously thinks we don't know who we're fighting, if there's anyone out there who thinks we're confused about who our enemies are," Obama said, "that would come as a surprise to the thousands of terrorists we've taken off the battlefield."

Gay dating app Jack'd said it has been unable to confirm so far that Mateen had a profile on the service. Grindr officials said they "will continue to cooperate with the authorities and do not comment on ongoing investigations." And Adam4Adam said the company is looking at conversations and profiles in the Orlando area for any activity by Mateen but hasn't found anything yet.

Mateen's father, Seddique Mateen, denied his son was gay and said that if he had been in the nightclub before, he may have been "scouting the place." The elder Mateen, who lives Port St. Lucie, Florida, said that apart from the time his son got angry a few months ago over seeing two men kissing, he never saw any anti-gay behavior from him.

Psychological studies have shown that some men with repressed same-sex desires may express anti-gay views, especially if they grew up in families that opposed homosexuality.

"People who are struggling to come to terms with their sexual identity do at times react to that by doing the exact opposite, which could be to become more masculine or more vocal about their ideals of a traditional family," said Michael Newcomb, a Northwestern University psychologist.

Mateen's ex-wife, Sitora Yusufiy, said earlier in the week that he was mentally ill, controlling and abusive. Amid the latest reports about his clubgoing, she told CNN: "Well, when we had gotten married, he confessed to me about his past that was recent at that time and that he very much enjoyed going to clubs and the nightlife and there was a lot of pictures of him."

"I feel like it's a side of him or a part of him that he lived but probably didn't want everybody to know about," she said.

The FBI has recovered Mateen's phone and will use location data to verify whether he previously visited the club, said a third official, who was not authorized to discuss the case and spoke on condition of anonymity.

Investigators working to determine whether anyone had advance knowledge of the attack have spoken extensively with Mateen's wife, Noor Salman, and are working to establish whether she and Mateen were recently at or inside the club, the official said. The official said investigators have not ruled out charging others, including the wife.

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Tucker reported from Washington. Associated Press writers Allen G. Breed and Tamara Lush in Orlando; Holbrook Mohr in Port St. Lucie, Florida; and Lindsey Tanner in Chicago, contributed to this report.