Did they mention a cause for him to appear to them, originally?
His full name was Omar Mir Seddique Mateen and he was born in New York. His parents are originally from Afghanistan, a U.S. official said.
The FBI had interviewed him in two terror-related cases, but both of them were closed, Assistant Special Agent in Charge Ronald Hopper told reporters Sunday.
"Those interviews turned out to be inconclusive," Hopper said, "so there was nothing to keep the investigation going."
"The FBI first became aware of Mateen in 2013 when he made inflammatory comments to co-workers alleging possible terrorist ties," Hopper said.