A man who committed the worst mass-shooting in the country’s modern history briefly provided security in the Pensacola area during the BP oil spill, his former employer confirmed.

Omar Mateen, a 29-year-old security guard from Fort Pierce, was shot and killed by police Sunday morning after gunning down more than 100 patrons of an Orlando nightclub, killing 49 people and injuring 53.

At the time of the shooting, Mateen was employed by security firm G4S at a gated residential community in South Florida. G4S confirmed Wednesday that Mateen was stationed in Pensacola from July-October 2010 to assist with the oil spill cleanup process.

According to the company, Mateen was responsible for “providing access control to prevent unauthorized entry into a designated area determined by BP.”

Mateen briefly appeared in “The Big Fix,” a 2012 documentary about the oil spill. Roughly 30 minutes into the film, a filmmaker covertly recorded a short conversation with Mateen at a security checkpoint. In the video, Mateen appears to spontaneously criticize the cleanup personnel and their motives.

“Everybody’s just out to get paid,” Mateen tells the filmmaker. “They’re like hoping for more oil to come out and more people to complain so they’ll have jobs.They want more disaster to happen because that’s where their money making is.”

Mateen had been employed with G4S since September 2007.

G4S is a security and risk mitigation firm that has operations in more than 100 countries and more than 50,000 employees in the United States, according to the company’s website.

A series of statements posted on the company’s website said G4S was “shocked and saddened” by the attack in Orlando.

“Mateen underwent company screening and background checks when he was recruited in 2007 and the check revealed nothing of concern,” a written statement from G4S said. “His screening was repeated in 2013 with no findings. He was also subject to checks by a U.S. law enforcement agency with no findings reported to G4S.”

It continued, “We are cooperating fully with all law enforcement authorities, including the FBI, as they conduct their investigations. In 2013, we learned that Mateen had been questioned by the FBI but that the inquiries were subsequently closed. We were not made aware of any alleged connections between Mateen and terrorist activities, and were unaware of any further FBI investigations.”