"They are trying to execute me in this case for that case," Demps said. "They want a free execution."

Unless his case is stayed, Demp is scheduled to die at 6 p.m. EDT Wednesday at Florida State Prison, located nine miles from the small city of Starke.

"I am an innocent man. I was wrongly convicted in the murder and I should be allowed to prove it," Demps said.

Demps, 49, a Vietnam War veteran, was originally condemned for the 1971 murders of R.N. Brinkworth and Celia Puhlick, who were fatally shot in a Lake County citrus grove. The victims were inspecting some land for sale when they happened upon Demps, who had fled to the grove with a stolen safe.

A year after Demps was sent to death row, the U.S. Supreme Court threw out capital punishment across the country, ruling death sentences were unconstitutional.

Demps and 96 other death row inmates were taken off Florida's death row.

In July 1976, the nation's high court upheld Florida's new capital punishment law. Two months later, on Sept. 6, 1976, Alfred Sturgis was fatally stabbed in his prison cell.

Before he died, Sturgis reportedly told a guard that Demps and another inmate had held him down while a third stabbed him. In 1978, Demps was sentenced to death.

The huskily built former Marine, who was wounded in Vietnam, claimed the dying words of inmate Sturgis and alleged eyewitness testimony from another inmate were both fabricated.

"I always knew that these people fabricated the evidence against me," said Demps, wearing the orange shirt which identifies death row inmates and a white knit cap because he is Muslim.

Demps said he was not involved in Sturgis' death. He claims he was in the shower at the time of the slaying.

"I am seeking justice in this case," Demps said. "I was wrongly convicted in a murder."

In a 1981 ruling affirming Demps' sentence, the Florida Supreme Court said Demps' previous conviction was a factor in his death sentence. The court rejected an argument that it should be overturned because the other two inmates, James Jackson and Harry Mungin, were given life sentences. Both are still incarcerated.

Only Demps had the "loathsome distinction of having been previously convicted of the first-degree murder of two persons and attempted murder of another, escaping the gallows only through the intervention of Furman v. Georgia," the high court wrote in its unsigned decision, citing the 1972 decision that vacated death sentences across the country.

Demps pointed to a newly discovered document written the day after the Sturgis slaying which lists Jackson as the assailant and does not mention Demps.

Since his second death sentence, Demps has survived death warrants in 1982, 1987, and 1990 by winning last-minute appeals.

Demps had appeals pending Tuesday in the 11th U.S. Circuit Court of Appeals in Atlanta and the U.S. Supreme Court - both were longshots.

Also Tuesday the Florida Supreme Court did not delay the execution, refusing to give Demps more time to pursue federal appeals.

Demps is the third inmate scheduled to be executed this year and will be the third to be put to death by lethal injection. He will be the first inmate executed for killing another inmate. Since Florida resumed the death penalty, 46 inmates have been put to death. Another inmate, Thomas Provenzano, 50, is scheduled to die June 20.

Demps said he was hoping for a last-minute miracle to save his life.

"No man is ready to die."