Did Omar Mateen Act Alone in Orlando Nightclub Massacre?

U.S. authorities on Monday investigated whether a gunman who killed 49 people at a gay nightclub in Orlando and declared his allegiance to Islamic State militants had received any help in carrying out the massacre.

The FBI and other agencies were looking at evidence inside and on the closed-off streets around the Pulse nightclub, where New York-born Omar Mateen perpetrated the worst mass murder in U.S. history, and the deadliest attack on U.S. soil since the Sept. 11, 2001, attacks.

Mateen, 29, the son of Afghan immigrants, was shot and killed by police who stormed the club with armored cars early Sunday morning after a three-hour siege.

FBI Director James Comey said authorities were trying to determine Mateen’s motives and there was no indication he was part of an organized terror network, although he may have been inspired by them.

“There are strong indications of radicalization by this killer and of potential inspiration by foreign terrorist organizations,” Comey told reporters in Washington. “We’re highly confident this killer was radicalized at least in some part through the internet.”

Law enforcement officials searched for clues as to whether anyone had worked with Mateen on the attack, said Lee Bentley, the U.S. attorney for the middle district of Florida.

“There is an investigation of other persons. We are working as diligently as we can on that,” Bentley said at a news conference. “If anyone else was involved in this crime, they will be prosecuted.”

Officials stressed they believed there had been no other attackers and had no evidence of a threat to the public.

Mateen’s rampage began about 2 a.m. Sunday (0600 GMT) when the club was packed with some 350 revelers. Many fled as the gunman raked the crowd with bullets from an AR-15-style semiautomatic rifle and a pistol.

An initial wave of officers charged into the club and trapped Mateen in a bathroom, Orlando Police Chief John Mina told reporters. That allowed many patrons to flee, although others were trapped in the restroom with Mateen, leading to the standoff.

POLICE: DOZENS SAVED

“We were able to save and rescue dozens and dozens of people,” Mina said. Police negotiated with Mateen for about three hours before breaking a hole in the wall, which allowed hostages to escape.

Mateen also emerged from the hole and was shot dead by officers, police said.

Officials said on Sunday the death toll was 50. On Monday they clarified that the figure included Mateen. Some 53 people were wounded and 29 remain hospitalized at Orlando Regional Medical Center, the hospital said on Twitter.

Pastor Deyni Ventura of Sanford said he visited a survivor in the hospital, whom she identified only as Norman, who had taken refuge in a handicapped bathroom stall crammed with 30 people.

He could hear the shooter laughing loudly as he sprayed gunfire over and under the bathroom stall. “They couldn’t see the shooter but they could hear him laughing,” she said, intimating a loud cackling laugh.

Norman, who was shot four times, crawled over the bodies of his friends to safety. Everyone else in the stall died, Ventura said.

“He told his friends to leave but they were scared and stayed in the stall – and all died,” she said.

Other family members were desperate for news about their missing loved ones.

Julissa Leal, 18, and her mother drove to the Florida city from Lafayette, Louisiana, in search of her brother, Frank Hernandez, 27. They knew he was at the club with his boyfriend, who lost him in the chaos.

“We haven’t heard anything, don’t know anything,” Leal said, fighting back tears. “I’m going to see him again. I’m going to see him again.”

During phone calls with authorities in the middle of the rampage, Mateen mentioned support for the leader of Islamic State, the Boston Marathon attackers and a Florida man who became an al Nusra Front suicide bomber in Syria, Comey said. Al Nusra is an al Qaeda offshoot at odds with Islamic State.