Newly released records show the gunman who opened fire at a Florida gay nightclub told his bosses he lied about having terrorist ties to get co-workers off his back about being Muslim.

In records released by the St. Lucie County Sheriff's Office on Monday, Omar Mateen tells his employers he was repeatedly taunted for his religion in his job as a security guard at the county courthouse.

His remarks prompted an FBI investigation in 2013 and caused enough concern that officials asked employer G4S Secure Solutions to have him reassigned, away from the courthouse.

But the documents show the FBI didn't believe he was a terrorist and an agent told a sheriff's office major he didn't think Mateen "would go postal or anything like that."

Mateen's rampage left 49 victims dead and 53 wounded at the Orlando club.