UPDATE, June 13, 2016: This post has been updated to reflect that Omar Mateen worked for G4S. The number of people killed in the shooting also has been updated.
The worst mass shooting in U.S. history was carried out by a security guard licensed to carry a firearm.
Authorities have identified Omar Mateen, 29, as the gunman who left 49 people dead and more than 50 others wounded early Sunday morning at Pulse, a popular gay nightclub in Orlando, Florida.
His licenses to work as an armed guard were active at the time of the shooting. The Bureau of Alcohol, Tobacco, Firearms and Explosives confirmed Sunday that he recently had purchased two firearms legally.
JUST IN: Orlando shooter's firearms were purchased legally, and he did so "in the last few days," ATF says. https://t.co/Aj9wavJMLg— Good Morning America (@GMA) June 12, 2016
Reveal originally checked Mateen’s arrest record in 2014 as part of an investigation into the armed security guard industry, which is regulated differently in each state. In Florida, authorities conduct criminal background checks before issuing guard licenses.
Mateen did not have a criminal record at the time. But reporters found that many guards were able to slip through the cracks of state licensing systems, including in Florida, where armed guards are not subject to mental health screenings before receiving licenses to carry firearms on the job. Reveal found many guards with histories of substance abuse who were allowed to work as armed guards.
It is unclear if Mateen had any other issues in his record, such as a record of a mental health commitment or substance abuse problems, that would have prohibited him from owning or using a gun. His ex-wife told The Washington Post that he was mentally unstable and violent.
“He was not a stable person,” she told the paper. “He beat me. He would just come home and start beating me up because the laundry wasn’t finished or something like that.”
Mateen had worked for G4S, one of the largest security companies in the United States. An in-house newsletter from 2012 identified an Omar Mateen of West Palm Beach as a guard for the company. His ex-wife told The Washington Post that he worked as a guard at a nearby facility for juvenile delinquents.
Orlando was still reeling from a very public recent killing. Christina Grimmie, who rose to fame as a contestant on NBC’s “The Voice,” was shot to death while signing autographs there Friday.