Subsequent reports said that the lay witnesses - all executions are witnessed - gasped as they watched blood flow on to Allen Davis's shirt.
The authorities said the bleeding occurred after the man was dead, and they blamed blood-thinning drugs taken by Davis. Critics, however, said the voltage used to electrocute the man, who weighed 25 stone, might have been inadequate.
Concern was compounded by the fact that the 8 July execution was the first to be conducted with a new electric chair, introduced after an incident in 1997 when flames shot from the head of Pedro Medina as he was electrocuted. The incident led to international criticism of the electric chair, including an appeal from the Pope.
Florida is one of only four states that still use the electric chair as the sole method of execution. Of 38 states where the death penalty exists, most use lethal injections.
The latest incident prompted the Florida Supreme Court to postpone the execution of Thomas Provenzano, set for 9 July. Next month, the court is to hear arguments on whether the electric chair amounts to a "cruel and unusual punishment", which would make it unconstitutional.
After the Medina execution, the Supreme Court ruled that the chair was legal. Four of the seven judges, however, urged that Florida consider adopting lethal injections instead. Since then, three judges have retired. Two of them supported the electric chair.
Opponents of the death penalty insist changes to the method will not make execution more palatable. Florida has 375 prisoners on death row, but revokes more death sentences on appeal than any other state. Opponents of the death penalty fear a move to lethal injections could reduce support for their campaign, as injections raise fewer public concerns.Reuse content