The 46-year-old serial killer was pronounced dead at 9:47 a.m. 6 minutes after the injection process began.
She was executed for the 1989 killing of Palm Harbour, Fla., electrician Harry Mallory, but has confessed to five others and was a suspect in a seventh. Mallory's trial was held in Daytona Beach.
"We did wake her up at 5:30. She requested a towel and washcloth to wash her face and freshen up," said prison spokesman Sterling Ivy before the execution. "She is very calm this morning. Not as talkative as she has been in the past."
Wuornos declined the traditional last meal, which could have been anything she wanted for under $20, and instead was given a cup of coffee.
A half-dozen anti-death penalty demonstrators were outside the prison, but were outnumbered by corrections officers.
Wuornos was strapped to a gurney and hooked to two intravenous lines. Thirty-two witnesses watched as she was wheeled into the death chamber where an executioner pumped deadly chemicals into her system.
"We can testify that that lethal injection is certainly more of a humane way to terminate life than the electric chair," said State Attorney John Tanner, who prosecuted the case in Daytona Beach. "She expressed in her last psychiatric examination relief that the electric chair had been abolished in the state of Florida."
Wuornos went to her death willingly. She fired her attorneys and opposed appeals made on her behalf. Two appeals were turned down by the Florida Supreme Court Tuesday. They both contended Wuornos was insane and not competent enough for her execution.
In her final statement, Wuornos said: "Yes, I would just like to say I'm sailing with the rock, and I'll be back, like Independence Day with Jesus. June 6, like the movie. Big mother ship and all, I'll be back, I'll be back."
She had written the Florida Supreme Court last year to say she "would prefer to cut to the chase and get on with the execution. Taxpayers' money has been squandered and the families have suffered enough."
Her life as a highway prostitute and the killings have been chronicled in three books, two television movies and a production by the San Francisco Opera.
The 367 inmates left on Florida's death row are appealing their sentences or considering appeals. Their executions will be delayed while the state supreme court considers the impact on Florida of a U.S. Supreme Court decision in an Arizona case.
The court ruled that Arizona's death penalty was unconstitutional because the sentences were handed down by judges rather than juries of the defendant's peers. In Florida, juries make recommendations on the death penalty, but judges make the final decisions.
Rigoberto Sanchez Velasco of Hialeah, Fla., had also "volunteered" for lethal injection and was executed last week. Democrats contend Republican Gov. Jeb Bush, who is running for re-election, was politically motivated when he signed the death warrants.
Wuornos will be the first woman to be executed in Florida since Judy Buenoano was electrocuted March 30, 1998. Buenoano was known as the "black widow" for poisoning her husband, drowning her handicapped son and for trying to kill her boyfriend. She was a suspect in the poison death of another boyfriend in Colorado, but she wasn't charged.
Buenoano was the first woman to be executed in Florida since a freed slave was hanged in 1848.
The media and others have said Wuornos may be the first female serial killer in the nation's history. The first known woman serial killer in history is thought to be Hungarian Countess Erzebet Bathory who was said to have killed more than 600 people, most of them young girls, before she was found out. She was imprisoned in one of her castles and died in 1614.
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