Staff at a television station in Virginia on Thursday observed a moment of silence for two co-workers shot dead the day before during a live broadcast by a disgruntled ex-colleague.
The killings of reporter Alison Parker, 24, and cameraman Adam Ward, 27, as they conducted an on-air interview - and the footage posted online by the gunman - prompted renewed calls for tougher US gun control measures.
The shooter - Vester Lee Flanagan, 41, also known as Bryce Williams - fatally shot himself after fleeing the scene. He sent a rambling manifesto to ABC News, saying he was a "human powder keg... just waiting to go BOOM!!!!" "We will, over time, heal from this," said a grief-stricken morning anchor, Kimberly McBroom, holding hands with two colleagues on the set.
The moment of silence at WDBJ, a CBS affiliate in Roanoke, Virginia, about 240 miles (385 kilometers) southwest of Washington, came at 6:45 am - the exact time that Parker and Ward were shot and killed at close range.
Photos of the slain journalists were displayed on-air during the tribute to them.
Ward captured a chilling image of the gunman as he fell to the ground - all of it watched live by a stunned newsroom and viewers at home.
"It breaks my heart every time you read or hear about these kinds of incidents," President Barack Obama told an ABC affiliate in Philadelphia.
Outside the studio gates, bouquets of flowers and shiny remembrance balloons were placed under a tree wrapped with two black mourning ribbons. Viewers and local residents came by to pay their respects.
"She was looking forward to life. I was looking forward to a life with her," WDBJ anchor Chris Hurst, Parker's boyfriend, told NBC News.
Parker was talking to Vicki Gardner, head of the Smith Mountain Lake Chamber of Commerce, early Wednesday at the lakeside Bridgewater Resort in the town of Moneta near Roanoke when the attack occurred.
Several shots were heard, as well as screams, as Ward's camera fell to the floor. No blood is seen in the video image.
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.
That video from the gunman's perspective was later removed from Twitter, Facebook and YouTube.
Gardner, 62, was wounded in the back in the attack. She was reported in good condition Thursday after undergoing emergency surgery.
In New York, ABC News said it received a 23-page manifesto from a man identifying himself as Bryce Williams nearly two hours after the shooting.
In the statement, Flanagan - an African American sacked in 2013 by WDBJ - said he was sent over the edge by the June mass shooting of black worshippers at a church in South Carolina.
He described 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." WDBJ general manager Jeffrey Marks said Flanagan was dismissed "after many incidents of his anger coming to the fore." On Thursday, Marks described the manifesto as "nonsense."
Hurst remembered Parker as "the love of my life" who was looking forward to preparing a major series on hospice care in Virginia.
"What great things she could have done," he said.
Ward's fiancee, Melissa Ott, a morning producer at WDBJ, meanwhile watched the shooting play out on air from the control room.
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.
Parker's father, Andy Parker, made a plea for tougher gun laws after the murder of his daughter, who he described as "our bright, shining light." "We've got to do something about crazy people getting guns," he told Fox News.
US lawmakers have been hesitant to enact tougher limitation on access to guns, in part because they are loath to anger voters who fiercely defend their constitutional right to bear arms.