Washington, United States: Vester Flanagan, who killed two journalists Wednesday and appeared to have filmed the murders, drew a troubled portrait of himself in tweets after their deaths and a rambling 23-page manifesto sent to ABC news.

Also known on-air as Bryce Williams, the 41-year-old African American said he was seeking to avenge racial injustices and instances in which he believed himself to have been wronged, in documents that paint him as deeply troubled by racism and hungry for revenge.

Flanigan allegedly shot and killed at close range reporter Alison Parker, 24, and cameraman Adam Ward, 27, in the middle of a live interview early Wednesday.

The pair worked for Roanoke, Virginia CBS affiliate WDBJ where Flanigan was once employed—and fired.

Flanagan fled the scene near a local lake, and his car was later found run off the highway, apparently after he shot himself. He died at a hospital in northern Virginia outside Washington.

In a series of tweets, Flanagan offered a glimpse at his motivations, posting that ‘Alison made racist comments’ and claiming that Ward had reported him to human resources.

Yet in a rambling manifesto received by ABC News, Flanagan said a recent deadly church shooting in Charleston, South Carolina, where nine black parishioners died, was what drove him over the edge.

‘The church shooting was the tipping point... but my anger has been building steadily,’ he said.

‘Why did I do it? I put down a deposit for a gun on 6/19/15. The Church shooting in Charleston happened on 6/17/15...’ 

‘Difficult to work with’

Born in 1973, the San Francisco State University graduate and Oakland native said he had suffered throughout his career as a black, gay man.

In the manifesto, which Flanagan termed a ‘Suicide Note for Friends and Family,’ he complained of racial discrimination and bullying ‘for being a gay, black man.’

Flanagan said in a tweet that he had filed a complaint against WDBJ’s Parker, whom he shot.

‘Vester was an unhappy man. We employed him as a reporter and he had some talent in that respect and some experience,’  WDBJ’s general manager Jeffrey Marks said.

Flanagan joined the station in March 2012 and was dismissed in February 2013, escorted out the door by police.

‘He quickly gathered a reputation of someone who was difficult to work with. He was sort of looking out for people to say things he could take offense to,’ Marks said.

‘Eventually, after many incidents of his anger, we dismissed him. He did not take that well,’ he added.

Flanagan bounced in an out of jobs in journalism and other fields. Before being hired at WDBJ, he had spent eight years working outside of journalism.

From 1993 to 2005, he worked at KPIX, San Francisco’s local CBS affiliate.

On his LinkedIn profile—registered under the name Bryce Williams—Flanigan wrote that he had worked at several television stations across the country since the mid-1990s as well as in marketing and customer relations.

‘A human powder keg’

Co-workers at NBC affiliate WTWC in Tallahassee, Florida began noticing Flanagan’s strange behavior when he worked there around 2000.

‘He was a good on-air performer, a pretty good reporter. And then things started getting a little strange,’ journalist Don Shafer told a San Diego news station where he is now news director.

Flanagan took WTWC to court for discrimination, claiming to have been called a monkey.

In his manifesto, Flanagan said that his anger had been a long time coming.

‘My anger has been building steadily... I’ve been a human powder keg for a while... just waiting to go BOOM!!!!’