"Let's rock," he said from an American death chamber within Riverbend Maximum Security Institution in Nashville.

Those were Edmund Zagorski's final words before the jolts of electrical current shot through his body. His hands remained clenched, except for his pinky fingers. They were either dislocated or broken, his attorney would later say, from straining against the straps of the electric chair in which Zagorski, 63, died Thursday at 7:26pm local time.

TENNESSEE DEPARTMENT OF CORRECTIONS Edmund Zagorski opted to be killed by the electric chair rather than lethal injection.

The state put the double-murderer to death by electrocution, spurning lethal injection at his request. His death made him the first inmate in five years to perish in the electric chair - and only the second in Tennessee since 1960. Daryl Holton, a Gulf War veteran who killed his four children in a marital dispute, opted for the electric chair in 2007.

Tennessee is among only a handful of states where the electric chair is still an option in executions. Prisoners who committed their crimes before 1999 may choose to die by electrical voltage instead of a cocktail of drugs. Thirty states allow some form of capital punishment. One of them is Pennsylvania, where federal prosecutors have begun the process of seeking a possible death sentence against Robert Bowers, the man accused of gunning down 11 congregants in a Pittsburgh synagogue, should he be convicted on certain charges.

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THE TENNESSEAN A small crowd gathered to protest Zagorski's execution.

Zagorski was convicted in 1984 of first-degree premeditated murder for luring two men into a wooded area under the pretense of a marijuana deal, and then shooting them and slitting their throats.

In a legal battle that reached the US Supreme Court last month, Zagorski sought to elude capital punishment based on the Eighth Amendment's ban on "cruel and unusual punishments." Between ways in which he could die, though, he favoured the electric chair over lethal injection, in a repudiation of a method seen by some as more humane and technologically advanced, despite a pattern of problems.

"By signing this affidavit I am not conceding that electrocution is constitutional. I believe both lethal injection and electrocution violate my rights under the 8th amendment," Zagorski wrote last month. "However, if I am not granted a stay of execution by the courts, as between two unconstitutional choices I choose electrocution."

He reasoned that death at the end of a syringe could mean as long as 18 minutes in "utter terror and agony," whereas the electric chair would quickly stop his heart.

At first, the state rejected his request, saying it had come too late. After a federal judge put a hold on the execution, however, officials reversed course. The governor, Republican Bill Haslam, ordered a 10-day delay to prepare use of the electric chair. The state confirmed that it would carry out Zagorski's death sentence by electrocution, "based upon his waiver of his right to be executed by lethal injection," as the warden of the prison wrote to the inmate's attorney last month.

However, his quest to assert a right not to be executed at all was unsuccessful. Again Thursday, the US Supreme Court declined to review the case, after a majority of justices decided last month not to thwart the execution. Justice Sonia Sotomayor, a sharp critic of the death penalty, dissented from the October judgment, joined by Justice Stephen Breyer.

"Once again, a State hastens to kill a prisoner despite mounting evidence that the sedative to be used, midazolam," she wrote, will induce feelings of "drowning, suffocating, and being burned alive from the inside out."

Sotomayor argued: "Capital prisoners are not entitled to pleasant deaths under the Eighth Amendment, but they are entitled to humane deaths. The longer we stand silent amid growing evidence of inhumanity in execution methods like Tennessee's, the longer we extend our own complicity in state-sponsored brutality."

Zagorski spent 34 years on death row, becoming a "model inmate," according to his attorney, Kelley Henry, a federal public defender. She said he had once saved the life of a guard. The last time he was on death watch, other inmates pooled their resources for a pizza dinner in his honour, according to the Tennessean.

On Thursday, his final meal was pickled pig knuckles and pig tails, the Tennessee Department of Correction said. Inmates in Tennessee are allotted US$20 ($30.10) for a special meal before their execution. He ate at 4pm, three hours before he was sponged down with saltwater to better conduct electricity.

"Chin up," he instructed his attorney in his final moments, telling her that he didn't want to gaze out and see her downcast expression.

She condemned his death as a miscarriage of justice, saying, "The world is not safer because of his execution."

"Horrifically, Mr Zagorski was forced to choose between 10 to 18 minutes of chemically burning from the inside while paralysed or being literally burned to death in less than a minute," she told reporters.

The irony of the case, said Bernard Harcourt, an expert in penal law and procedure at Columbia University, is that lethal injection, because it was billed as a method befitting more modern times, "muted our societal consideration of the unconscionability of the electric chair."

Texas became the first state to use lethal injection to carry out capital punishment in 1982. Since then, more than 7 per cent of lethal injections have been botched, said Austin Sarat, a professor at Amherst College and the author of Gruesome Spectacles: Botched Executions and America's Death Penalty.

"Lethal injection was supposed to be the fulfillment of a century-long quest for a method of execution that could be safe, reliable, and humane," he said in an interview. "But with each invention of a technology - electrocution replacing hanging, gas chamber coming on to complement electrocution, and then in late 1970s, the development of the lethal injection protocol - the same hopes were articulated."

The prisoner's decision to revert to an older method of punishment, Sarat said, "signals what we know to be happening - the breakdown of this idea that lethal injection would be any kind of magic bullet.