He planned it all so carefully — a choreographed execution of two former colleagues, broadcast live to a horrified television audience. Hours later, he shared his own recording of the killing worldwide on social media.

Vester Lee Flanagan's video shows him approaching WDBJ reporter Alison Parker and cameraman Adam Ward, gun in hand, as they conduct an interview. He points the gun at Parker and then at Ward, but he waits patiently to shoot until he knows that Parker is on camera, so she will be gunned down on air.

TV viewers heard about the first eight of 15 shots. They saw Parker scream and run, and heard her crying "Oh my God!" as she fell. Ward fell, too, and the camera he had been holding on his shoulder captured a fleeting image of the suspect holding a handgun.

That man, authorities said, was Flanagan — a former staffer who used the on-air name of Bryce Williams and was fired by WDBJ, a man who always was looking for reasons to take offence, colleagues recalled. He fled the scene but then posted his own 56-second video of the murders on Twitter and Facebook. He later ran off a highway while being pursued hundreds of kilometres away and was captured; he died of a self-inflicted gunshot wound.

President Barack Obama said in an interview the fatal on-air shooting of the two TV station employees is heartbreaking.

"What we know is that the number of people who die from gun-related incidents around this country dwarfs any deaths that happen through terrorism," he said.

Maximum, viral exposure

Wednesday's on-air murders reverberated far from central Virginia because that's just what the killer wanted — not just to avenge perceived wrongs, but to gain maximum, viral exposure. He used his insider's knowledge of TV journalism against his victims a 24-year-old reporter who was a rising star and a 27-year-old cameraman engaged to a producer who watched the slaughter live from the control room.

Alison Parker and Adam Ward

Alison Parker, 24, and Adam Ward, 27, were shot to death on air Wednesday while working for a local station in Roanoke, Virginia. Video of it quickly circulated on social media and so did a video shot by the killer himself who uploaded it to Facebook. (WDBJ7)

Flanagan's planning may have started weeks ago when, ABC News said, a man claiming to be Bryce Williams called repeatedly, saying he wanted to pitch a story and needed fax information. He sent ABC's newsroom a 23-page fax two hours after the 6:45 a.m. local time shooting that was part-manifesto, part-suicide note — calling himself a gay black man who had been mistreated by people of all races, and saying he bought the gun two days after nine black people were killed in a June 17 shooting at a Charleston church. The fax also included admiration for the gunmen in mass killings at places like Virginia Tech and Columbine High School in Colorado.

He described himself as a "human powder keg" that was "just waiting to go BOOM!!!!"

Bureau of Alcohol, Tobacco, Firearms and Explosives spokesman Thomas Faison said late Wednesday that Flanagan legally bought the gun used to kill Parker and Ward.

Parker and Ward were a regular team, providing stories for the station's Mornin' show on everything from breaking news to feature stories on subjects like child abuse. Their live spot Wednesday was nothing out of the ordinary: They were interviewing a local official at an outdoor shopping mall for a tourism story before the shots rang out.

Dead at the scene

As Parker screamed and Ward collapsed, Ward's camera kept rolling, capturing the image of the suspect pointing the gun. WDBJ quickly switched to the anchor back at the station, clearly shocked, who told viewers, "OK, not sure what happened there."

Parker and Ward died at the scene. Their interview subject, Vicki Gardner, also was shot, but emerged from surgery later Wednesday in stable condition.

Vester Lee Flanagan

This image posted on Twitter by CBS News shows Virginia shooter Vester Lee Flanagan, a former employee of CBS affiliate WDBJ7, who reported under the name Bryce Williams. (CBS News/Twitter)

Flanagan, 41, who was fired from WDBJ in 2013, was described by the station's president and general manager, Jeffrey Marks, as an "an unhappy man" and "difficult to work with" always "looking out for people to say things he could take offence to."

"Eventually after many incidents of his anger coming to the fore, we dismissed him. He did not take that well," Marks said. He recalled that police had to escort Flanagan out of the building because he refused to leave when he was fired.

Tweets posted Wednesday on the gunman's Twitter account — since suspended — described workplace conflicts with both victims. He said he filed a complaint with the Equal Employment Opportunity Commission against Parker, and that Ward had reported him to human resources.

Marks said Flanagan alleged that other employees made racially tinged comments to him, but that his EEOC claim was dismissed and none of his allegations could be corroborated.

"We think they were fabricated," the station manager said.

Quick to file complaints

Dan Dennison, now a state government spokesman in Hawaii, was the WDBJ news director who hired Flanagan in 2012 and fired him in 2013, largely for performance issues, he said.

"We did a thorough investigation and could find no evidence that anyone had racially discriminated against this man," Dennison said. "You just never know when you're going to work how a potentially unhinged or unsettled person might impact your life in such a tragic way."

USA-SHOOTING/VIRGINIA

A law enforcement officer is seen on the road in front of the Bridgewater Plaza in Moneta, Va. (Chris Keane/Reuters)

Court records and recollections from former colleagues at a half-dozen other small-market stations where he bounced around indicate that Flanagan was quick to file complaints. He was fired at least twice after managers said he was causing problems with other employees.

Both Parker and Ward grew up in the Roanoke area, attended high school there and later interned at the station. After Parker's internship, she moved to a smaller market in Jacksonville, N.C., before returning to WDBJ. She was dating Chris Hurst, an anchor at the station and had just moved in with him.

"We were together almost nine months," Hurst posted on Facebook. "It was the best nine months of our lives. We wanted to get married. We just celebrated her 24th birthday. She was the most radiant woman I ever met."

Ward, who played high school football, was a devoted fan of his alma mater, Virginia Tech. His colleagues said he rarely, if ever, missed a game. They called him a "happy-go-lucky guy" — even during the early morning hours that are the proving ground for so many beginning journalists.

Ward's fiancée, station producer Melissa Ott, was in the control room marking her last day on the job when the shots rang out. Ward had planned to follow her to her new job in Charlotte, N.C.

Marks helped lead the live coverage Wednesday after the station confirmed its two employees were dead. He said he and his staff covered the story despite their grief, to honour their slain colleagues.

"Our hearts are broken," he said. "Our sympathy goes to the entire staff here, but also the parents and family of Alison Parker and Adam Ward, who were just out doing their job today."

With files from Reuters and CBC News