MIAMI (CBSMiami/AP) – After spending nearly 40 years on Florida’s death row, a man convicted of killing a Miami couple and stabbing a prison guard to death is scheduled to be put to death by lethal injection.

Askari Abdullah Muhammad, previously known as Thomas Knight, is scheduled to be executed Tuesday at Florida State Prison in Starke barring a last-minute, successful appeal.

Gov. Rick Scott signed the death warrant after the Florida Supreme Court in December rejected Muhammad’s challenge to chemicals used in the state’s execution procedure.

Muhammad, 62, was first condemned to die for the 1974 killings of Sydney and Lillian Gans. Then known as Knight, he had worked for Gans at a paper bag company before abducting him in the business’ parking lot with a rifle. He ordered Gans to drive home to pick up his wife and then go to a bank to withdraw $50,000.

Inside the bank, Gans asked a manager to alert authorities. Both the FBI and local police were able to follow the car for a while, including use of aircraft, but lost track of it for a short time in a rural part of southern Miami-Dade County. Trial testimony showed that’s when Muhammad shot the couple in the back of the head and tried to hide by burying himself, the rifle and the money in mud and weeds.

Muhammad was found a short time later and arrested. While awaiting trial, he and 10 other inmates escaped from the local jail, leading to a nationwide manhunt including a Top 10 fugitives listing by the FBI.

Although he was not charged, authorities say Muhammad was involved, after his escape, in the fatal October 1974 shooting of liquor store clerk William Culpepper during an armed robbery in Cordele, Georgia. Another clerk was shot and wounded, according to local authorities.

The FBI finally arrested Muhammad on New Year’s Eve in 1974 in New Smyrna Beach In his possession were three stolen weapons: a sawed-off shotgun, a .38-cal. revolver and a 9mm handgun.

After his conviction in the Gans case, Muhammad in 1980 fatally stabbed Correction Officer Richard Burke with the sharpened end of a spoon as he was being escorted to the prison shower. Court documents show that Muhammad had become upset because he was told he couldn’t see a visitor unless he shaved his full beard, and had been overheard by guards to remark that “it looks like I’ll have to start sticking people.”

Muhammad was sentenced to die for Burke’s killing in 1983.

His execution has been delayed for so long because of numerous appeals and rulings in the Gans case, including a 1987 federal appeals court tossing out his death sentence because he hadn’t been allowed to put character and background witnesses on the stand during the penalty phase.

The decades have worn heavily on the Gans family as they await justice. Their daughter, 72-year-old Harriet Shapiro, said it will be a relief when it’s all over.

“Even though I have no hatred in my heart and I don’t live with anger, I would be very happy to see him dead and stand there when they kill him,” Shapiro told CBS4 news partner The Miami Herald in a recent interview.

Muhammad was resentenced to death in 1996, but last year another federal judge found that he had been improperly barred from cross-examining some witnesses in that second sentencing hearing. The 11th U.S. Circuit Court of Appeals reversed that decision in September and restored the death penalty, prompting Scott to sign a death warrant.

“To learn about the gridlock and inefficiency of death penalty litigation, look no further than this appeal,” the appeals judges said in their opinion.

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