Guard house at PGA Village in St. Lucie County. (NICOLE RODRIGUEZ/TREASURE COAST NEWSPAPERS)

By Nicole Rodriguez of TCPalm

ST. LUCIE COUNTY — Orlando shooter Omar Mateen, who was employed by G4S Security, worked as a security guard at PGA Village in Port St. Lucie at least two days before the Orlando massacre.

Some residents on Tuesday questioned how the problems of the man charged with protecting them — and who was behind the deadliest mass shooting in U.S. history — went undetected by G4S for so long.

MORE | From childhood to the massacre, what happened to Omar Mateen?

Deanna Ambrose, a resident, wants to know why Mateen was hired by the security firm and given a gun.

"All of us are questioning our safety," Ambrose said Tuesday. "He could have gone off the deep end at any given moment and just went house to house."

Ambrose, who said she continues to pray for the shooting victims and their families, fears Port St. Lucie's reputation as a family-friendly place to watch baseball has earned a sinister reputation.

"We've always been known as home of the (New York) Mets, and now we're going to be known as home of the assassin — the killer," she said.

Frustrated residents at a resident meeting Wednesday night, which was attended by at least 200 people, bombarded Drew Levine, G4S president of secure solutions in North America, with their concerns — among them, how Mateen flew under the private security firm's radar.

Mateen in 2007, as part of the G4S hiring screening process, underwent a standard psychological exam — named the Minnesota Multiphasic Personality Inventory — and a background check, its representatives said. The state also screened Mateen every two years in order for him to keep his private security license. Beyond that, G4S does not conduct yearly background checks of its employees; rather, 15 percent of all employees are randomly checked each year, representatives said.

Mateen's background, however, was checked again by G4S in 2013 after the St. Lucie County Sheriff's Office requested he be removed from the St. Lucie County Courthouse patrol after he allegedly made derogatory comments to a deputy.

A deputy at the courthouse mentioned the Middle East to Mateen, who reacted by threatening the deputy, said Sheriff Ken Mascara, who attended the Wednesday night meeting at the community's Island Club.

"Omar became very agitated and made a comment that he could have al-Qaida kill my employee and his family," Mascara said Wednesday. "If that wasn't bad enough, he followed it up with very disturbing comments about women and followed it up with very disturbing comments about Jews and then went on to say that the Fort Hood shooter was justified in his actions."

The FBI launched an investigation into Mateen after Sheriff's Office officials reported the incident to the agency. As part of its investigation, the FBI examined Mateen's travel history, phone records, acquaintances and even planted a confidential informant in the courthouse to "lure Omar into some kind of act and Omar did not bite," Mascara said. The FBI concluded Mateen was not a threat after that, Mascara said.

In an interview with G4S management shortly after the courthouse comments, Mateen told his superiors he was the target of inflammatory comments from co-workers because of his Islamic faith, Levine said. The interview, Levine said, took place shortly after the Boston Marathon bombings, which was carried out by two Islamic extremist brothers. Levine said Mateen claimed his co-workers on one occasion asked him what suicide vest he was wearing on a particular day.

G4S concluded Mateen worked in a hostile environment and did not fire him, Levine said.

Mateen exhibited no signs he was a threat to co-workers or to the residents he guarded at PGA Village, Levine said.

"We don't believe we had a gap, because whatever transformed Omar Mateen into the monster he became, we didn't have a view of that and that's substantiated by the numerous interviews we had with our employees," Levine said.

Ambrose's neighbor, Maria Roman, on Tuesday recalled the time a year ago when Mateen stopped her and her husband, Edwin, for rolling through a stop sign.

The encounter lasted about a minute, Roman said. A pleasant Mateen let the couple go with just a warning.

"Oh my goodness. We see this guy every day," Roman said of learning authorities identified Mateen as the Pulse nightclub gunman. "We wave at him, and look at what's happened right in our own backyard."

Three of Mateen's fellow security guards at PGA Village declined to comment Tuesday, referring questions to Jupiter-based G4S headquarters. They said they weren't permitted to talk about their experiences with Mateen.

A statement issued by G4S said the company was "deeply shocked by the tragic events in Orlando this weekend and the thoughts of everyone at G4S are with the victims and their families.

"Omar Mateen was employed by G4S at a residential community in South Florida and was off-duty at the time of the incident. Mateen was subject to detailed company screening when he was recruited in 2007 and rescreened in 2013 with no adverse findings. He was also subject to checks by a U.S. law-enforcement agency with no findings reported to G4S.

"G4S is providing its full support to all law enforcement authorities in the USA as they conduct their investigations."

State Rep. Larry Lee Jr., D-Port St. Lucie, and a PGA Village resident since 1998, provided words of encouragement and comfort Tuesday to his constituents still reeling from the news that Mateen lived and worked among them.

"All it takes for evil to prevail is for good people to do nothing," Lee said. "What all of us should begin to do is to stay encouraged and each and every day do something to make your community a better place. Particularly, reach out to our youth. That is the way we're going to end all of this hatred, racism and discrimination."

On living so close to Mateen, Lee said:

"You turn on the television and you see national headlines, and you see this stuff happening in other places. Then to turn the TV on and you see your hometown, your community having connections to something like this just saddened me. My prayers are with the families of all of those people who lost their lives."

PGA Village has 2,517 homes on 2,600 acres immediately west of Interstate 95 in unincorporated St. Lucie County. PGA Village Property Owners Association Property Manager Diane Blakeman declined to comment, citing an active FBI investigation.

The controlled-access community includes more than 25 miles of roadway, three guard houses and a large clubhouse.