Omar Mir Seddique Mateen was born in 1986 in New York. Most recently he lived in Fort Pierce, about 120 miles southeast of Orlando.
Fearing explosives, police evacuated about 200 people from the apartment complex where he lived while they looked through his residence for evidence.
Mateen’s parents, who are from Afghanistan, said he’d expressed outrage after seeing two men kiss in Miami, but they didn’t consider him particularly religious and didn’t know of any connection he had to ISIS.
He was married in 2009 to a woman originally from Uzbekistan, according to the marriage license, but he filed documents to end the marriage in 2011.
Sitora Yusufiy, interviewed by CNN in Boulder, Colorado, said she and Mateen were together about four months, though it took a long time to complete the divorce because they lived in different parts of the country after separating.
Mateen was a normal husband at the beginning of their marriage but started abusing her after a few months, she said.
She said Mateen was bipolar, although he was not formally diagnosed. She also said Mateen had a history with steroids. He was religious but she said she doesn’t think his religion played in to the attack.
Mateen had worked since 2007 as a security officer at G4S Secure Solutions, one of the world’s largest private security companies.
A message posted in Arabic on a dark web site associated with the ISIS news agency Amaq said “the armed attack that targeted a gay night club in the city of Orlando in the American state of Florida and that bore more than a 100 killed and wounded was carried out by an Islamic state fighter.”
But CNN’s Salma Abdelaziz, who translated the message and closely monitors ISIS messaging, cautioned about taking the message at face value.
She said the language is inconsistent with previous ISIS announcements and that the Arabic word for gay was used rather than an epithet normally used by ISIS. Also, there was no claim that the attack was directed, just an after-the-fact claim the gunman was an ISIS fighter, she said.
At a Sunday afternoon news briefing, FBI Assistant Special Agent Ronald Hopper said the agency was aware of Mateen. The FBI interviewed him in 2013 and 2014 after he expressed sympathy for a suicide bomber, Hopper said.
“Those interviews turned out to be inconclusive, so there was nothing to keep the investigation going,” Hopper said.