Black people experience more mistakes during executions than any other race, report finds [Video]

Lethal injections are the primary method of execution in the U.S. Most states use one drug or a cocktail of three to render prisoners unconscious, paralyze them to conceal evidence of pain and, finally, to stop their heart, researchers said. Proponents claimed it would be a quick and humane way to put people to death, but there is no evidence to support this.