FORT PIERCE — Inside the humble little mosque where Omar Mateen regularly came to pray, a handful of worshipers gathered Sunday evening and struggled, along with the rest of the world, to understand what had driven him to kill.
On Friday, Mateen had faced east with the other regulars at the Islamic Center and bowed to a God who prizes justice and peace above all else, said Imam Shafeeq Rahman, who leads prayers at the center.
Two days later — after Mateen, wielding a semiautomatic rifle and pistol, walked into the Pulse nightclub in Orlando, invoked the Islamic State and the Boston Marathon bombings and committed the deadliest mass shooting in U.S. history — Rahman and the others condemned their former brother in the strongest possible terms.
"Ninety-eight percent of Muslims are peaceful people, and 2 percent have hijacked the religion," said Rahman, who described the 29-year-old as an antisocial man who attended prayers at the mosque three to four times a week. He said he and the other worshipers were thinking only of the victims. "Our heart cries for them," he said.
Because in the end, Rahman said, Mateen was as much a mystery to him and his congregants as he was to the rest of the world.
Who was Mateen, and what motivated him to kill 50 strangers and wound 53 more?
Public records and interviews with neighbors, coworkers and family friends paint a picture of a man who had become increasingly withdrawn from the world. Having weathered job loss and a broken marriage, he was the father of a young boy. He had begun to act more and more devout in recent years but still was capable of sudden vulgarity and flashes of anger at gay people, blacks, Jews and women.
Mateen's ex-wife, Sitora Yusufiy, described him as unstable and abusive during a Sunday news conference in Colorado, where she now lives. She told CNN and other media she met Mateen online and moved to Fort Pierce to marry him in 2009. They divorced two years later. "My family literally rescued me," Yusufiy said. "The night that they were there, they had to pull me out of his arms. I left all of my belongings and filed a police report."
Mateen's father, Seddique Mir Mateen, told NBC News he did not believe the killings had to do with religion and said his son was angered recently when he saw two gay men kissing in Miami.
"They were kissing each other and touching each other and he said, 'Look at that. In front of my son they are doing that,' " the father said. "And then we were in the men's bathroom and men were kissing each other."
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Born in New York in 1986, Mateen moved with his family to Florida, where he spent at least part of his childhood.
He took classes at Indian River State College in Fort Pierce and in October 2006 got a job as a prison guard for the Florida Department of Corrections. He didn't last long in the position. Records show he left the job in April 2007 for an "administrative matter unrelated to misconduct."
He started working for G4S, a private security firm that contracts with state governments and federal agencies, soon after.
G4S placed him at the St. Lucie County Courthouse, manning the metal detectors at the front, said Daniel Gilroy, a former coworker. Before long, Mateen was involved in an incident with a black colleague, Gilroy said, and was sent to man the gate at the PGA Village neighborhood in St. Lucie West.
That's where Gilroy said he got to know Mateen.
He said Mateen often would cover his head and bring a prayer mat to work — but his apparent piety belied what Gilroy called a "vulgar mouth" and a deep well of anger.
He said Mateen would smack things in the guard house when he got angry, openly lusted after female guests of the country club and used slurs to describe gay people, blacks, Jews and women. "He never used other words to describe them," Gilroy said. "Oh, he hated women. He thought they were objects, he thought they shouldn't be allowed to drive, he thought he should have his pick."
Gilroy says he complained to his supervisors at G4S about Mateen's behavior. A spokeswoman for G4S issued a statement late Sunday confirming Mateen joined the company in 2007 and passed initial and follow-up background checks that revealed nothing of concern.
"Our thoughts and prayers remain with the victims of this unspeakable tragedy, and their friends and families," the statement said.
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It was unclear late Sunday what ties Mateen had to Orlando — if any.
Federal authorities said the FBI interviewed him three times in recent years, including once in 2014 after he came into contact with another Fort Pierce man who went on to become the first American suicide bomber in Syria. That man, 22-year-old Moner Abusalha, lived briefly with his brother in Orlando before traveling to the Middle East.
In Fort Pierce, on Florida's east coast about an hour north of West Palm Beach, authorities gathered at the Woodlands Condominiums where Mateen lived and waited for a warrant to enter his home.
The neighborhood surrounding the small two-story complex is quiet and firmly middle class, neighbors said. It's full of modest, concrete-block, single-family homes with weight benches in driveways, Dale Earnhardt stickers on pickup trucks and Beware of Dog signs affixed to chain-link fences. Residents were shocked to see police vehicles lining S 17th Street by 8 a.m. Sunday.
Robert Shephard, 30, said several of his girlfriend's friends were supposed to be at Pulse on Saturday night but car trouble postponed the trip to Orlando. "Thank God," he said.
At a separate property connected to Mateen's family, on SW Bayshore Boulevard in Port St. Lucie, law enforcement officers carted away computers, boxes and bags, witnesses said.
Becky Diefendorf, 56, who said she worked with Mateen's mother at a nearby Walgreens, stood and watched them work. She said she only met Mateen once or twice, but said he never made eye contact. She called him a "lost soul."
"You try talking to him," Diefendorf said, "he'd just put his head down and walk away."
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Back at the Fort Pierce Islamic Center, on a rural stretch of Midway Road on the dividing line between Fort Pierce and Port St. Lucie, Imam Rahman recalled the worshiper as coming from a good family. He was muscular and most congregants assumed he was a police officer, Rahman said.
When prayers would end, he would rise without saying a word. When the other men would pause and exchange a few words, he would head for the door.
On Sunday, Rahman, red-eyed from worry and lack of sleep, said he feared reprisals in the wake of the Orlando attack. He asked camera crews and photographers not to record the faces of the men at his mosque.
Then he kneeled down and led about a dozen worshipers in an evening prayer.
"Oh Allah, stop this bloodshed and this killing," he began, imploring. "Make the world peaceful . . . help us."
Times staff writers Zachary T. Sampson and Anna N. Phillips contributed to this report.