ROANOKE, US - The former television reporter who shot dead two journalists during a live US broadcast before killing himself warned he had been a “human powder keg... just waiting to go BOOM.” The gunman - Vester Lee Flanagan, 41, also known as Bryce Williams - posted chilling footage of Wednesday’s shocking double murder online.

Reporter Alison Parker, 24, and cameraman Adam Ward, 27, were shot and killed at close range while conducting an on-air interview for WDBJ, a CBS affiliate in Roanoke, Virginia, about 240 miles southwest of Washington.

Friends, family and the community at large mourned the tragedy, which renewed calls for tougher gun laws in the United States. Flanagan was said to have bought his gun legally. “It breaks my heart every time you read or hear about these kinds of incidents,” President Barack Obama told an ABC affiliate in Philadelphia.