Omar Mateen
Omar Mateen

ORLANDO, Fla. (Diya TV) — After the bodies were removed from Pulse nightclub, investigators Monday began to work towards trying to determine what motivated the Florida killer responsible for the worst mass shooting in U.S. history.

Omar Mateen was a man the FBI knew was sympathetic towards terrorism, and had previously been investigated by the agency because of such traits.

The 29-year-old Mateen called 911 prior to Sunday’s attack to pledge his allegiance to the terrorist group ISIS. It is believed Mateen had been planning to carry out the attack on the Orlando gay nightclub for some time. He attempted to buy military-grade body armor from a local store in recent weeks, according to a U.S. official. His efforts were halted after personnel at the store refused to sell him what is known as Level III body armor, protection which offers more than police typically use. He additionally legally purchased a Glock pistol and a long gun, according to Trevor Velino of the Bureau of Alcohol, Tobacco, Firearms and Explosives.

At this time, it remains unknown whether those weapons were used in the attack.

The FBI and local law enforcement are currently investigating Mateen’s employment history — he worked as a security guard for G4S Secure Solutions, one of the world’s largest private security companies, since 2007, where he was licensed to carry a firearm. The company had him assigned to a post at the St. Lucie County Courthouse.

Mateen was interviewed by the FBI in 2013 and again in 2014 after he publicly expressed sympathy for a Syrian suicide bomber, Assistant Special Agent Ronald Hopper said. Hopper said the interviews were “inconclusive,” which meant there was no reason to keep them going. His employer was aware of the interviews, but he passed the company’s background check process.

He was no longer under investigation at the time of Sunday’s shooting. That means, Hopper said, Mateen could “legally walk into a gun dealership and acquire and purchase firearms.”

FBI Director James Comey said Monday that the agency is “highly confident” the gunman was radicalized, at least in part, by viewing extremism on the Internet.

Earlier officials said the number of dead totaled 50 but clarified that figure was including the gunman. Around midday Monday, Florida Attorney General Pam Bondi said the families of at least 36 out of 49 victims have been notified of their loves ones’ deaths.

Orlando Police officers direct family members away from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)
Orlando Police officers direct family members away from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)

Mateen’s possible ties to ISIS are a big part of the current investigation. Aside from the allegiance he swore to ISIS during his 911 call, he also made mention of the Boston Marathon bombers, a U.S. official said.

ISIS sympathizers have reacted to the attack with praise in the group’s forums, while the official online ISIS radio channel, Al-Bayan, described it as a “raid on a Crusader gathering” carried out by “one of the Caliphate’s soldiers in America.” There are other individuals in addition to Mateen being investigated as part of the attack.

“If anyone else was involved in this crime, they will be prosecuted,” said U.S. Attorney Lee Bentley, adding there was “no reason to believe that anyone connected to this crime” was placing the public in imminent danger.