ORLANDO, Fla. – An Orlando nightclub owner received a Facebook friend request from Omar Mateen, the gunman who killed 49 people and injured 53 others at another nightclub, prompting the FBI to investigate.

Shortly before 5 p.m. Tuesday, investigators from the Orlando Police Department and the FBI arrived at Club Revere to speak with owner Michael Bass.

Bass told News 6 investigator Michael Holfeld that he had received a Facebook request from Mateen either late Thursday and early Friday morning.

Bass told Holfeld he made the connection when he saw reports on News 6 about the Pulse nightclub shooting.

"When I didn't accept (the Facebook friend request), I looked through his friends first and rejected it. In doing that, I looked -- a few of his friends were just Arabic writing and I didn't even know. It was just nothing that would relate to an LGBT club. It just didn't make sense," Bass told Mike Holfeld.

"But you are sure that's him," Holfeld asked Bass about the friend request from Omar Mateen.

"I am 99.99 percent," Bass said.

"When I saw that picture that morning of the incident, I swallowed my tongue. I work here. I help with security. I run, I operate, I fix. I watch what goes on." Bass said. "It was Omar Mateen."

The Facebook request came shortly after an employee at Club Revere received several calls from a man asking questions about the bar. It's not yet known if the caller was Mateen.

Bass said he will meet again with FBI agents on Wednesday. He told News 6 that he became emotionally upset after meeting with them Tuesday.

FBI officials told News 6 that it's not been determined if Mateen seriously considered Club Revere as a target, but an investigation is continuing.

Authorities continue to trace Mateen's whereabouts over the last two months.

Club Revere was closed Saturday night, and one of the the regular dancers at the club went to Pulse. News 6 learned the dancer was 35-year-old Xavier Emmanuel Serrano Rosado, who died in the mass shooting.

"I will remember him for the rest of my life. (He's) that kind of person," Bass said.

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