She was the first woman executed in Florida since a slave called Celia was hanged in 1848 for killing her maser after he raped her. Mrs Buenoano was also the first woman to be electrocuted in the United States since 1957. Most states now use lethal injections.
A prosecutor dubbed her the Black Widow because she poisoned her husband for life insurance money after he returned from Vietnam in the Seventies. But that murder appeared almost tame compared with the way she killed her teenage son. He was disabled, wearing leg braces, when she took him on a canoe trip then dumped him over the side and watched impassively as the heavy braces dragged him down and he drowned.
Why? To collect the $125,000 (about pounds 75,800) in life insurance she had taken out on him. Prosecutors said she may even have induced his paralysis by trying to poison him on earlier occasions.
She also killed a boyfriend with arsenic and tried to blow up another lover with a home-made car bomb, in both cases after taking out life insurance polices on them. It was only after the failed car bomb in 1983 that police looked into the earlier deaths of her husband and son.
The boyfriend she tried to blow up, John Gentry, told police she had previously given him "vitamin" tablets that made him violently ill. Prosecutors at her trial said the tablets in fact contained arsenic and that she had been trying to kill him for the insurance money. That led them to exhume the bodies of her husband and son, and in both cases they found arsenic.
She had changed her name to the Hispanic version, Buenoano, which means "good year" after her husband, Air Force Sergeant James Goodyear, died of what at the time appeared to be natural causes, in 1971.
Perhaps as a result of the nature of her crimes, there was little outcry in Florida or elsewhere as Mrs Buenoano's life was taken. Unlike Karla Faye Tucker, killed by lethal injection in Texas last month, the Black Widow was not photogenic and did not seek worldwide support for her clemency appeals.
According to witnesses, including police officers, Florida state officials and journalists, she was led into the death chamber at 7.02am on Monday, two minutes after noon British time. A microphone in the chamber allowed the witnesses to hear a prison official ask her if she had any final statement. "No, sir," she replied in a whisper.
She then closed her eyes and kept them closed, wincing as the leather straps on "Old Sparky",. so nicknamed because its victims had been known to catch fire, were tightened. The current was switched on at 7.08 and left on for 38 seconds. The witnesses said a puff of smoke drifted from her right leg. At 7.13, a prison official checked her pulse and pronounced her dead.
A day earlier, Florida's Supreme Court had rejected her final appeal for clemency, in which she described the electric chair as "barbaric ... belonging to Frankenstein's laboratory". Florida has twice stopped using the chair temporarily after victims appeared to catch fire. It was suspended for a year after one death row inmate, Leo Jones, challenged its constitutionality, saying it represented "cruel and unusual punishment".
The state's Supreme Court disagreed and Jones was electrocuted last week. Another murderer is due to die in the chair today.Reuse content