Florida has put a man to death with an anaesthetic never used before in a US lethal injection.

Danny Harold Rolling, Florida’s most notorious serial killer since Ted Bundy, was ”remarkably calm” as he awaited his execution for the grisly 1990 slayings of five college students in Gainesville, his attorney said today.

A sex fiend who wants to be executed had his wish thwarted at the eleventh hour last night while officials probed a claim that another prison inmate had carried out a murder he was on death row for.