On Monday, Comey explained at a press briefing that the FBI had been alerted to Mateen twice, and yet he was removed from the terrorist watchlist, prior to killing 49 people at a popular gay club in Florida and wounding an additional 53.
Mateen’s initial questioning by the FBI came after coworkers reported him for making "inflammatory" comments involving radical Islam. He had reportedly told his coworkers that he hoped law enforcement would come into his home and assault his wife so “he could martyr himself.”
When questioned by the FBI, Mateen claimed he was angry as a result of comments his coworkers made about his Muslim faith.
The shooter was questioned again after a Florida man, with whom he had ties, traveled to the Middle East and killed himself in a suicide bombing. Mateen was then removed from the FBI terror watch list.
An ex-coworker described Mateen as racist, belligerent and "toxic,” in an interview with NBC News following this weekend’s attack.
“He was scary in a concerning way," Daniel Gilroy, a co-worker at G4S, told NBC. "And it wasn't at times. It was all the time. He had anger management issues. Something would set him off, but the things that would set him off were always women, race or religion. [Those were] his button pushers."
"I needed to be out of that situation," he said. "I described it as being toxic."
Gilroy said that Mateen, "always referred to every other race, religion, gender in a derogatory way.”
"He did not like black people at all. That was mentioned once or twice, but more so was women. He did not like women at all. He did like women in a sexual way, but he did not respect them."
Though red flags for Mateen were ignored, the FBI continues to encourage people to report suspicious behavior and those thought to be a threat. The agency maintains it wouldn’t do anything differently.