The suspect -- Vester Lee Flanagan, 41, also known as Bryce Williams -- died in a hospital from a self-inflicted gunshot wound after being taken into custody by state police following an intense morning manhunt.
In a rambling manifesto sent to ABC News in New York, Flanagan, an African American, said he was sent over the edge by the June mass shooting of black worshippers at a church in South Carolina.
Describing himself as a "human powder keg... just waiting to go BOOM!!!!," Flanagan also complained in what he called a "Suicide Note for Friends and Family" of racial discrimination and bullying "for being a gay, black man."
The killings once again highlighted fears about gun violence in America -- prompting a quick White House call for action -- and also raised questions about how the Internet provided a brief but unfiltered window on a horrific crime.
The disturbing video of the deadly on-air shooting -- apparently filmed by Flanagan himself -- was posted on Twitter and Facebook. The footage, seen by AFP, was later taken down.
Reporter Alison Parker, 24, and cameraman Adam Ward, 27, were fatally shot at close range while conducting an on-air interview for WDBJ, a CBS affiliate in Roanoke, about 240 miles (385 kilometers) southwest of Washington.
"You send people into war zones and into dangerous situations, into riots, and you worry that they're going to get hurt," WDBJ general manager Jeffrey Marks -- who confirmed the deaths to viewers -- told CNN.
"You send somebody out to do a story on tourism, and this -- how can you ever expect something like this to happen?"
Shots and screams
Parker was talking to Vicki Gardner, head of the Smith Mountain Lake Chamber of Commerce, at the lakeside Bridgewater Resort in the town of Moneta near Roanoke when the attack occurred.
A screengrab image of Parker before she was shot while conducting an interview. - AFP Photo/WDBJ7/Handout
Several shots were heard, as well as screams, as Ward's camera fell to the floor, capturing a fuzzy and chilling glimpse of the gunman pointing his weapon at the ground. No blood is seen.The station then hastily cut away to a startled anchorwoman back in the studio.
Later, a video posted under the Twitter account @bryce_williams7, showed the shooter brandishing a weapon at Parker, who was interviewing Gardner. Both she and Ward apparently did not see the shooter.
Multiple shots are then heard, and screams. Parker runs away.
The shooter's hand is clearly visible. He appears to be wearing a blue checkered shirt.
Gardner was in stable condition, according to Chris Turnbull, a spokesman for the hospital in Roanoke where she was being treated.
'Tipping point'
ABC News said it received a rambling 23-page manifesto from a man identifying himself as Bryce Williams nearly two hours after the shooting. A man later called the network and said he had shot two people.
This TV video frame grab courtesy of WHSV TV, in Harrisburg, Virginia shows shooting suspect Vester Lee Flanagan, also known as Bryce Williams. - AFP Photo /WDBJ7-TV
He said authorities were "after me" and "all over the place" before hanging up, ABC said.
"The church shooting was the tipping point... but my anger has been building steadily... I've been a human powder keg for a while... just waiting to go BOOM!!!!" the statement said.
"Yes, it will sound like I am angry... I am. And I have every right to be. But when I leave this Earth, the only emotion I want to feel is peace..." it said.
Marks, the station manager, said Flanagan was dismissed two years ago "after many incidents of his anger coming to the fore."
'I am numb'
"I am numb," the reporter's boyfriend, WDBJ anchor Chris Hurst, said on Twitter.
"We were together almost nine months. It was the best nine months of our lives. We wanted to get married."
The cameraman's fiancee, Melissa Ott, a producer at the TV station, was in the control room when the shooting occurred and watched it unfold, Marks told CNN.
Ott was working her last day at WDBJ before moving on to another station in another city, and looking forward to a farewell party with her colleagues.
"This was going to be a day of celebration for her time here and wishing her good luck," Marks said, adding staff were very emotional and planning a memorial gathering.
'Heartbroken'
The shooting, which took place not far from the scene of the Virginia Tech University mass killing in April 2007, launched a fresh round of hand-wringing about gun control in America.
"There are some common sense things that only Congress can do that we know would have a tangible impact," White House spokesman Josh Earnest told reporters.
Democratic presidential candidate Hillary Clinton said she was "heartbroken and angry."
"There are too many guns in the hands of people who should not have guns," Virginia Governor Terry McAuliffe told Washington's WTOP all-news radio.
The secretary general of media watchdog group Reporters without Borders (RSF), Christophe Deloire, called the killings an "unprecedented tragedy, even in a country where thousands of people are killed each year by firearms."
Even in the face of mass shootings, US lawmakers have been hesitant to enact tougher limitation on access to arms, in part because they are loath to anger constituents who fiercely defend their constitutional right to bear arms.
