Transcript for Alleged Gunman Apparently Calls Himself 'Human Powder Keg' in Manifesto
We're not going to be showing the video taken by that shooter but we are learning a lot more about him. A former reporter who worked with the two, he faxed an angry manifesto to ABC news, texted with a friend right after the murders and ABC's chief justice correspondent Pierre Thomas has those details. Reporter: He was a Maltais content, a man who often felt victimized had difficulty getting along with colleagues but no one fully understood how deep the darkness ran. Overnight, police descended on the suspect's apartment concerned about bombs and booby trap, all this hours after a nightmare that began on live TV. Flanagan's anger had apparently been building since being fired two years ago from WDBJ, the station where he and the victims worked. He had been ordered to get counseling, represent prix mapdzed by the station's management for berating a cameraman in public. The station citing him for, quote, aggressive body language when dealing with co-workers. Eventually after many incidents of his anger coming to the fore, we dismissed him and he did not take that well. Reporter: The anger had been simmering for years. In 2000, Flanagan was involved in a lawsuit with a Florida television station claiming racism and that he had been called a monkey. Allegations that were denied. And in 2014 he filed a lawsuit against WDBJ, but it was dismissed. Wednesday morning nearly two hours after the shooting a man identifying himself as Flanagan faxed what he called a suicide note to ABC news, 23 pages long, it portrayed a deeply angry man laying out his grievances. Why did I do it? The church shooting in Charleston was the tipping point but my anger has been building steadily. I have been a human powder keg for awhile. Just waiting to go boom. But Flanagan apparently never let go of the resentment. In the suicide note he claimed the cameraman he murdered complained to management about him and also said he was a victim of racism and sexual harassment suggesting he had been mistreated because he was a gay black man. One of his former bosses at another station suggested he was a problem employee, but that no one thought him capable of this. Shock. Hair on the back of my neck went up. I didn't see that in his personality certainly. Reporter: In the suicide note Flanagan expresses admiration for mass murders, specifically the columbine killers and the Virginia tech shooter and in one of his final callous gestures a man claiming to be Flanagan called ABC news in New York at 10:00 A.M. And said he shot two people. He hung up and we called the police. He said after the Charleston church shooting jehovah god spoke to him, another case of apparently a man with serious mental health issues with a gun killing the innocent that keep falling through the cracks.
This transcript has been automatically generated and may not be 100% accurate.