Teresa Lewis spent her last days praying and singing hymns, but she appeared frightened and tense as she entered Virginia's death chamber.
Lewis, 41, died by injection at 9:13 p.m. Thursday at the Greensville Correctional Center in Jarratt, Va., according to The Associated Press.
Lewis' final words were a message for the daughter of the husband she had killed.
"I just want Kathy to know that I love her, and I'm very sorry," she said.
Her death brought an end to the debate over whether Lewis deserved to die, with supporters saying she was borderline mentally retarded, despite the prosecution's claim that she was the mastermind of her husband's and stepson's murders.
Her attorney, James Rocap III, said Lewis was peaceful before going to her death and had been praying and singing in the days leading up to her execution.
"We thought that we were supposed to be helping her, while she was actually helping us," Rocap said.
But when Lewis entered the death chamber to be strapped onto a guerney and injected with the lethal cocktail of drugs, her jaw was visibly clenched. She looked around tensely and appeared frightened, witnesses reported.
In the chamber with her were 14 corrections officers who assisted her onto the guerney and secured her to it with heavy leather straps.
Moments before her execution, Lewis asked if her husband's daughter -- her stepdaughter -- was near. She was. Kathy Clifton was in an adjacent witness room blocked from the inmate's view by a two-way mirror. Lewis then gave her final words of farewell to her.
As the drugs flowed into her body, her feet bobbed but she otherwise remained motionless. A guard tapped her lightly on the shoulder, reassuringly, as she slipped into death.
Teresa Lewis' Final Message to Fellow Inmates
Lewis was sentenced to die for concocting a grisly plan to hire two hit men to kill her husband and stepson in October 2002. Lewis stood by while Julian Lewis and son Charles Lewis were shot at close range as they slept.
She had promised the killers a cut of a life insurance policy to carry out the murders. Both triggermen were sentenced to life in prison, and one committed suicide in 2006.
Despite the controversy surrounding her execution, the Supreme Court refused to hear her appeal earlier this week, and Virginia Gov. Bob McDonnell had denied her petitions for clemency.
On the website Save Teresa Lewis, run by supporters who tried to have her death sentence commuted, a message was posted in which Lewis thanked them for their work on her behalf. They also posted a farewell Lewis had recently written to fellow inmates.
"Man wants me to die, but I'm not worrying over this, I'm trusting Jesus," she wrote. She urged the prisoners to turn to Jesus promising, "He will forgive you of all your sins and He will bring you into His loving arms."
Lewis, case number 09-4, became the 12th woman to be put to death in the United States since 1976, and left behind 60 women remaining on death row nationally, who constitute less than 2 percent of the total death row population. She joined a group of about 40 women who have been executed in the United States in the past 100 years, according to the Death Penalty Information Center, a group that opposes the death penalty and tracks its impact.
Those opposed to Lewis' death sentence said the fact that she was a woman should not allow her to be treated differently. What they found troublesome was that Lewis, with an IQ of 72, was borderline mentally retarded and received a more severe sentence than those who pulled the trigger.
"It would be grossly unfair if the one person among those involved who is probably the least danger to society, who is certainly no more guilty than those who carried out the murders and whose disabilities call out for mercy, is the only person scheduled to die for this crime," said Richard Dieter, the executive director of the Death Penalty Information Center.
John Grisham Opposed Execution of Teresa Lewis
John Grisham, the well-known crime novelist, agreed.
"Why," he wrote in an op-ed article for The Washington Post, "did the triggermen get life without parole while Lewis received a sentence of death? Ostensibly, it is because she was the ringleader and thus more culpable. But what could make a killer more culpable than repeatedly shooting a sleeping victim?"
According to court papers, the trial judge who heard Lewis' case said that her sentence was made more difficult by the fact that she had pleaded guilty to her crimes and led the police to the triggermen. But he found she had engaged in the "cold blooded, pitiless slaying of two men, horrible and inhumane." And that she had done it for profit, searching her husband's wallet for money as he lay dying.
The Associated Press contributed to this report.