The killing of Michael Brown was "a blatant assassination," Ty Pruitt, the cousin of the black teenager shot by a police officer in Missouri, told Good Morning Britain, after an autopsy revealed he was shot six times, twice in the head.
Mr Pruitt said: "My question is, as far as policemen go, your training tells you to first stun, that's why you carry a stun gun...if he was that much of a threat, why didn't you just stun him, then subdue him?"
Unrest sparked by Mr Brown's death is ongoing in Ferguson, a suburb of St. Louis.
Mr Pruitt called for the peaceful protesters to "stand firm," but said to the looters and "the people who provoke violence - 'Go home...every time the cops have to come out and deal with you it pushes my cousin's case backwards.'"
More top news
Showers turning wintry across the higher ground, accompanied by a widespread frost
Several police were injured after violence erupted in Baltimore today after the funeral of a man who died in police custody.
Bournemouth all but sealed promotion to the top-flight for the first time in their history with a 3-0 win against Bolton.