New documents show the gunman who killed 49 patrons at a Florida nightclub was repeatedly taunted for being Muslim in his job as a security guard at a Florida courthouse.

Records released Monday by the St. Lucie County Sheriff's Office show Mateen claimed he was regularly called derogatory epithets for being Muslim by deputies and others at the St. Lucie Courthouse, where he worked as a contract guard.

In response to the taunting, he told co-workers he had ties to the Boston Marathon bombing suspects and the Fort Hood shooter.

That prompted an investigation by the FBI.

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