ROANOKE, Va. — For two years after losing yet another television job, Vester Lee Flanagan II lived in a nondescript apartment across the street from WDBJ Channel 7, the station that had fired him. He worked in modest jobs at several insurance companies nearby. As thoughts of murder and revenge were swirling around his brain, he did his best to keep them out of sight.

But he was, in his own words, putting on “a smiley face to disguise what was to come.” Three separate suicide notes, typed within the last few weeks and sent to a news organization on Wednesday, document the homicidal rage that had apparently been building for years, culminating when Mr. Flanagan shot and killed a reporter and a cameraman for his former station before shooting himself in the head as the police closed in.

The fax, along with letters and photographs from his childhood, and interviews with people who have known him over the years, reveal someone who was consumed for much of his life with an encyclopedia of grievances. He was a black man who saw racism in every workplace; a gay man who felt demeaned, especially by other black men; a floundering son who addressed his accusatory suicide note to his successful father; an aspiring television newsman who, despite some talent, could not succeed at work or get along with his colleagues.

There were arguments and confrontations at work, periodic eruptions, including a road rage episode captured on video and a sacrifice of his two pet cats, killings that Mr. Flanagan said he carried out because of anger at his firing. And then the final horrific explosion, broadcast live on television and posted on Facebook.

“The damage was already done and when someone gets to this point, there is nothing that can be said or done to change their sadness to happiness,” Mr. Flanagan writes in his suicide note. “It does not work that way. Meds? Nah. It’s too much...too much...too much!”

Mr. Flanagan grew up in Oakland, Calif., in a gray two-story home in what was then a predominantly white neighborhood. His mother, Betty Flanagan, was a teacher, and his father, Vester Sr., a college football star who had been drafted by the Green Bay Packers, served as a dean at San Francisco State University, where his son later graduated.

Archie Russell, who attended the same high school as Mr. Flanagan, remembers him as an indifferent trumpet player in the school band, and athletic: He had a fast, precise way of running that led some to call him “Robo,” as in “RoboCop.”

But Mr. Flanagan also writes about being subjected during those years to teasing, he says at the hands of fellow students. In the rambling suicide notes, Mr. Flanagan described high school football coaches who removed him from the team because they were jealous of his fledgling modeling career.

“My issues arised after I was attacked by white females!! And black males!!” he writes. “I have friends of all types. But most of my haters have been from these two groups. I have a right to be outraged!!!”

That outrage seemed to subside early in Mr. Flanagan’s life after high school, and at times his writings recall a sense of purpose and stability. In the suicide notes, Mr. Flanagan lovingly recollects time between 1996 and 1998 that he spent working at WTOC-TV in Savannah, Ga. It was there, he writes, that he fell in love with someone he calls Kenny.

“Ken was there for me in ways I cannot even describe,” he writes. “What a great experience that was — all around. A scenic/romantic city...a new romance...a career hitting on all cylinders. Sadly, we only had a short period of ‘happiness’ as it related to my career, anyway.”

He moved from Georgia to Florida, where a job at WTWC in Tallahassee became what Mr. Flanagan called “a disgusting, vile and wretched situation.” In a 2000 lawsuit, he alleged that he was the victim of racial slurs and bullying, a complaint that he would repeatedly make during the rest of his life.

The station fired him, citing “misbehavior with regards to co-workers,” but the discrimination case he brought was settled out of court.

The experience in Tallahassee not only generated anger at his former colleagues there, but also toward his father, whom Mr. Flanagan blamed for failing to support his claims of harassment.

“When I came to you to seek advice because, to put it in my words, ‘nothing was working in my life,’ you offered no advice,” he writes. “I can’t remember a single word of encouragement or advice...heck, not one syllable.”

Later, Mr. Flanagan rants that his father notified him of his mother’s death with a voice mail message.

Mr. Flanagan continued to pursue work in television after the “fiasco” in Tallahassee. He notes that a job in Greenville, N.C., was “amazing.” In a 2011 email seeking a job at WAFF, a station in Huntsville, Ala., Mr. Flanagan sounded enthusiastic and upbeat. He wrote proudly of his ability to multitask, cultivate sources and work with “little or no supervision...being a self-starter.”

The Alabama station declined to hire Mr. Flanagan. Adam Henning, the news director there, said references had told of finding Mr. Flanagan “exceedingly difficult to work with.”

That proved to be the case in Roanoke as well. By the summer of 2012, managers at the station had begun to document problems in his employment file, accusing Mr. Flanagan of “misinterpreting” the actions and words of his co-workers. “Under no circumstances should you engage in harsh language, demonstrate aggressive body language, or lash out at a photographer in front of members of the public,” the station warned in one memo.

The station also ordered Mr. Flanagan to get employee-assistance counseling and warned: “It is your responsibility, going forward, to work at repairing these relationships, as the station cannot be put in the position of making assignments based on the inability of team members to get along.”

After he was fired from the Roanoke station in February 2013, Mr. Flanagan seethed again. He filed another harassment lawsuit, and served as his own lawyer. So angry one day after what he called “an awful chain of events,” he writes that he killed his two cats and drove to a forest, where he dug a grave and covered the bodies with leaves and a flower.

There is little in the suicide notes to explain what directly set off Mr. Flanagan’s final act, though he says that the recent killing of nine African-Americans at a church in Charleston, S.C., was “the tipping point” and that “I’ve been a human powder keg for a while...just waiting to go BOOM!!!! at any moment.” In another part of the suicide note, Mr. Flanagan hints at the killings he would eventually commit.

“Again, I am in a holding pattern. Today didn’t ‘work’ in terms of the ‘situation.’ tomorrow? maybe,” he says. Later, he writes that he has told family members he would like to be cremated if something were to lead to his death.

The anger occasionally spilled out. A video of a road rage incident this summer shows Mr. Flanagan apparently following another driver and confronting him after they get into an argument. The video, taken by the other driver, was posted online after Wednesday’s shootings.

But most people he came into contact with after that say they did not detect the level of anger in him. Mary Clark, 78, who lives in Mr. Flanagan’s apartment complex, described him as polite, but sad and lonesome. “He didn’t talk very much, and his eyes were always roaming around, like looking for a friend,” she said.

He was something of an enigma to the end. The rental car in which he shot himself to death contained a briefcase with three license plates, wigs, a shawl, an umbrella and sunglasses as if he were planning to escape, not commit suicide. During the first four months of 2015, Mr. Flanagan worked for $18 an hour as a receptionist at Risk Management Programs Inc., a temp worker whose colleagues found him to be unexceptional. For a year before that, he answered customer calls at a United Healthcare insurance facility in Roanoke.

“We didn’t see anything that caused us concern,” said Chris Carey, the president of Risk Management Programs, where employees never noticed that their temporary receptionist — whom they knew as Donald Flanagan — had once been a local TV personality.

It was not until Wednesday, when news reports revealed the identity of the gunman, that Mr. Carey and the others realized who he was.

“It’s a bit troubling to find out the type of risk you exposed yourself to,” Mr. Carey said. “It could have been here.”