ORLANDO - The gunman responsible for the deaths of 49 people inside a gay nightclub in Orlando pledged loyalty to the Islamic State of Iraq and Syria (ISIS) in his last moments, and the Mideast terrorist group quickly and happily took the credit.
However, if the statements of several patrons of Orlando's gay scene are proven true, ISIS would probably prefer to take Omar Mateen and throw him off a tower.
A U.S. official with knowledge of the situation tells CBS News that club-goers have told investigators that Mateen had been at Pulse numerous previously. Additionally, other media outlets have heard several stories of Mateen popping up and conversing with men on gay dating apps.
While it is still possible Mateen was just very closely surveying his chosen target for terror, former senior FBI profiler Mary Ellen O'Toole told CBS News that doesn't seem likely.
"This to me suggests somebody that may have had sexual identity issues and may have actually been struggling with the idea that he himself was gay and that would add a different motive and a different perspective on the case," O'Toole said.
The former FBI profiler said that while he may have been confused, that wasn't reason enough for the rampage.
"The thinking really preexists by months if not years before the actual carrying out of the event," O'Toole said. "We look for patterns of behavior and some of the things that we look for are lifetime pattern of basically being somewhat of a loser, not having accomplishments in life. The other thing we look for is a pattern of violent ideation."
Mateen ex-wife has accused him of beating her and being mentally ill, and the 29-year-old New York-born son of Aghan immigrants had bounced around a bit holding only mediocre jobs before his rampage. He had also on numerous occasions made aggressive and violent threats to coworkers, friends, and others.
Jim Van Horn, 71, said Mateen was a "regular" at the popular Pulse nightclub where he'd later take hostages and leave 49 dead.
Van Horn, a retired pharmacist, said he met Mateen once, and the younger man talked about his ex-wife. But Van Horn said his friends soon "told me they didn't want me talking to him, because they thought he was a strange person."
The Orlando Sentinel and other news organizations quoted other regulars from Pulse who said they had seen Mateen there a number of times, and many said he was at best strange, at worst a little scary.
"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," said Ty Smith, who remembered seeing Mateen inside at least a dozen times.
Former FBI profiler O'Toole said one of the key elements to snapping the way Mateen did is to show traits of sociopathy. Officials have said that while speaking to Mateen on the phone during the rampage, he seemed "cool and calm," which O'Toole said is an important reflection of his character.
"He's extremely callous. It shows an extreme lack of empathy for the victims, a lack of guilt, a lack of compassion, and those traits did not just occur the day before the shooting -- no, those were personality traits that preexisted the shooting," O'Toole said.
It is unlikely that Mateen hated gays alone, O'Toole said. People who do what he did are generally not that specific.
"It involves an ability to view the world not as an angry man, but as a person filled with hatred, and not just hatred for gays," O'Toole said. "I've never had a case yet where the individual was just hateful of one particular group like women or blacks or gays -- they hate everybody. So they have this nihilist view of the world."
for more features.