The bulletin says the U.S. is concerned about homegrown violent extremists and asks for vigilance and awareness.
As dozens of memorials across the city grow to honor the 49 killed in the incident, the FBI is asking the shooter's wife what she knew, and when she knew it.
Law enforcement officials say Omar Mateen's wife, Noor Salman, went to buy ammo with him, visited Pulse nightclub with him at least once and may have tried to talk him out of committing an act of violence.
Now the FBI is asking for help.
"No matter how small the information may be, we want to hear from you," said FBI Assistant Special Agent in Charge Ron Hopper.
Other new details include a threatening Facebook message Mateen posted 24 hours before the attack.
He wrote: “Taste the vengeance.”
And there are new signs Mateen possibly struggled with an inner conflict, causing him to profess to hate homosexuals.
A former classmate described an interaction with him.
“He asked me if I was gay and because I wasn't out at the time I told him, 'No, I'm not,' and he said, 'If you were gay, you'd definitely be my kind of guy,'” the classmate said.
More of the victims spoke out Wednesday about coming face to face with the killer.
"He looked deranged. He looked like something was mentally wrong with him," said Tiara Parker.
Parker spent hours in the bathroom with her cousin, Akyra, who was killed.
As police continue to investigate, Channel 2 Action News had the only crew allowed inside the crime scene when officers opened the main road leading to Pulse.
Businesses are now open along Orange Avenue for the first time since the shooting.
City of Orlando workers told Channel 2’s Dave Huddleston they are working around the clock to manage the area around the Pulse nightclub.
"It's amazing just for something to happen like that. You would never expect it to happen here,” said one city worker who only identified himself as Soloman.
Aaron Campbell, a pastor from Philadelphia, flew to Orlando for just 24 hours, hoping to council any families of victims looking for guidance.
"I remember where I was when I first got the news of Columbine. We're hearing more and more of them and the shock is still the same. And it should be the same. We shouldn't become callous to something like this," Campbell said.
Campbell told Huddleston his message is much like the common theme around Orlando right now: Spread love.
"People coming together, community, realizing on this type of soil that life really is a gift," Campbell said.
© 2019 Cox Media Group.