MONETA, Va. -- A TV reporter and cameraman were shot to death during a live television interview on CBS Roanoke affiliate WDBJ-TV Wednesday by a gunman who recorded himself carrying out the killings and posted the video on social media after fleeing the scene.

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Authorities identified the suspect as a journalist who had been fired from the station in 2013. Hours later and hundreds of miles away, he ran off the road and a trooper found him with a self-inflicted gunshot wound. He died at a hospital later Wednesday.

Virginia State Police Sgt. Rick Garletts said a license-plate reader alerted troopers to the suspect's vehicle.

The shots Wednesday morning rang out on-air as reporter Alison Parker and cameraman Adam Ward were presenting a local tourism story at an outdoor shopping mall. Viewers saw her scream and run, and she could be heard saying "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.

WDBJ quickly switched back to the anchor at the station, her eyes large and jaw dropping as she said, "OK, not sure what happened there." The station later went live again, reporting on their own station and staff as the story developed.

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Parker and Ward were killed as the gunman fired about 15 shots. Their interview subject, Vicki Gardner, was in stable condition later Wednesday after surgery for her wounds.

The gunman was Vester Lee Flanagan II, 41, of Roanoke, who appeared on WDBJ as Bryce Williams, authorities said.

In an interview with CBSN, Jeffrey Marks, WDBJ's president and general manager, said Flanagan's name came to mind "instantly" when he heard about the shooting.

Two journalists fatally shot during live on-air segment

"He left here in a cloud ... We asked him to leave and that itself was difficult," Marks said.

Marks said Flanagan had to be escorted by police out of the station when he was fired. Marks described him as "an unhappy man" and "difficult to work with," always "looking out for people to say things he could take offense to."

"Eventually after many incidents of his anger coming to the fore, we dismissed him. He did not take that well," Marks explained.

Vester Flanagan

CBS News' Jeff Pegues reports that law enforcement sources say Flanagan purchased two glock pistols legally on July 10 from a gun store in Roanoke. Investigators have been to the store.

Video posted hours after the shooting on Bryce Williams' Twitter account and Facebook page showed an outstretched arm holding the handgun and firing repeatedly at Parker as she tried to run away.

The shooter appeared to walk up to the victims and stand a few feet away from them while holding the weapon. The three, in the midst of a live TV interview, do not seem to notice the gunman, who doesn't start shooting until Ward points the camera at Parker.

Ward was engaged to a producer at the station, Melissa Ott, who was celebrating her last day on the job and was in the control room, watching it live, as the shooting unfolded, Marks said.

Tweets posted on Williams' Twitter account Wednesday described workplace conflicts with both victims. They say Williams filed a complaint with the Equal Employment Opportunity Commission against Parker, and that Ward had reported Williams to human resources.

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

"We think they were fabricated," Marks said.

We love you, Alison and Adam. pic.twitter.com/hLSzQi06XE — WDBJ7 (@WDBJ7) August 26, 2015

ABC News reported on its website that the network received a 23-page fax from someone claiming to be Williams. The network said the fax was turned over to authorities.

ABC News reports that a man using Williams' name called the network in the past few weeks asking to pitch a story and wanting to fax information. The organization says the man never said what the story was.

Then, ABC News says, a fax arrived with a time stamp of 8:26 a.m. Wednesday, nearly two hours after the shooting in Virginia. He called the network just after 10 a.m., introducing himself as Bryce but saying that his legal name was Vester Lee Flanagan and that he had shot two people. That document is being analyzed by investigators, Franklin County Sheriff W.Q. "Bill" Overton Jr. said at a news conference.

The 23-page document is a manifesto of sorts, saying he was motivated to kill his former co-workers after the recent Charleston church shootings. The document says Williams bought a gun June 19, two days after authorities say Dylann Roof killed nine people inside a black church. Police have called the Charleston massacre a racially motivated hate crime.

According to the network, the man claiming to be Flanagan says in the "suicide note" that he was seeking revenge for racial discrimination, sexual harassment and workplace bullying he said he suffered as a gay black man. The document also cites the Virginia Tech and Columbine High School killers as influences.

"This gentleman was disturbed at way things had turned out at some point in his life. Things were spiraling out of control," Overton said.

President Obama spoke about the shooting during an interview Wednesday evening with CBS affiliate KIRO in Seattle, saying that his heart goes out to the victims and their families.

"I think it's one more argument for why we need to look at how we can reduce gun violence in this country," Mr. Obama said. "Right now, the FBI has been helpful with local authorities in trying to solve what is really a tragic day."

Both the victims were romantically involved with other employees at the station, according to Parker's boyfriend, WDBJ anchor Chris Hurst. He wrote online that they hadn't shared their relationship publicly but "were very much in love." He said they had just moved in together and wanted to get married. "I am numb," he said.

We didn't share this publicly, but @AParkerWDBJ7 and I were very much in love. We just moved in together. I am numb. pic.twitter.com/tUrHVwAXcN — Chris Hurst (@chrishurstwdbj) August 26, 2015

We were together almost nine months. It was the best nine months of our lives. We wanted to get married.We just celebrated her 24th birthday — Chris Hurst (@chrishurstwdbj) August 26, 2015

The shooting happened around 6:45 a.m. at Bridgewater Plaza in Franklin County, as Parker interviewed Gardner about the upcoming 50th anniversary festivities for Smith Mountain Lake, a local tourism destination.

Ward, 27, graduated from Virginia Tech and was engaged to a producer at the station, Melissa Ott, said WDBJ spokesman Mike Morgan.

"Adam was our go-to guy. He pretty much was available to do anything that we asked," Morgan said. "He did live shots during our morning show for several years."

Parker had just turned 24 and had joined the station as an intern after attending James Madison University, where she was the editor of the school's newspaper, The Breeze. According to her Facebook page, Parker spent most of her life outside Martinsville, Virginia. She was an avid kayaker and attended community theater events in her spare time.

The station is based in Roanoke, Virginia, and serves the southwest and central part of the state. The shootings happened at a mall just off Smith Mountain Lake in Moneta, about 25 miles southeast of Roanoke.