Columbia, South Carolina - A man convicted of the murder of a store clerk is to be put to death by lethal injection in South Carolina on Friday, one of five executions scheduled to be carried out across the country over the next week.

Freddie Owens (46) will be the first person executed in South Carolina in 13 years if his last-minute clemency application to Governor Henry McMaster is rejected.

Owens was sentenced to death in 1999 for the murder of Irene Graves, a mother of three, during an armed robbery of a convenience store in Greenville, South Carolina, on Halloween night in 1997.

Surveillance footage played at his trial showed two men wearing masks enter the store around 4:00 AM, according to court documents. They stole $37 from a cash register and led Graves to the back of the store, where she was shot in the head after she was unable to open a safe.

A co-defendant, Steven Golden, testified that Owens was the gunman wearing a ski mask who shot Graves.

Golden, who received a lesser sentence, has since recanted his testimony. In a sworn statement filed Wednesday, he said Owens was not present at the store during the shooting.

Owens maintains his innocence and has asked the governor to spare his life. He was given a choice between lethal injection, the electric chair, and firing squad but declined to choose.

His lawyer selected lethal injection.

Four other executions are scheduled to take place next week – three by lethal injection and one using nitrogen gas.

Travis Mullis, who turns 38 on Friday, is to be put to death by lethal injection in Huntsville, Texas, on Tuesday for allegedly stomping his three-month-old son, Alijah Mullis, to death in 2008.

That same day, Marcellus Williams (55) is to be executed in Missouri – also by lethal injection – for the 1998 murder of Felicia Gayle, a newspaper reporter.

Williams has maintained his innocence and the NAACP civil rights group has urged Governor Michael Parson to stay his execution. According to the Innocence Project, Gayle's killer left behind considerable DNA evidence – none of which matches Williams.

"You have the power to prove that Missouri is better than its ugly history of racism and unspeakable treatment of its Black residents," the NAACP said in a letter to the governor.

"Killing Mr Williams, a Black man who was wrongfully convicted of killing a White woman, would amount to a horrible miscarriage of justice and a perpetuation of the worst of Missouri's past," it said.

Two executions are scheduled for Thursday – in Alabama and Oklahoma.

Alan Miller (59) was convicted of shooting three work colleagues to death in Pelham, Alabama, in 1999.

A 2022 attempt to execute Miller by lethal objection was aborted because of difficulty inserting needles into his veins. He is to be executed by nitrogen hypoxia, which involves pumping nitrogen gas into a facemask.

Alabama carried out the first-ever execution in the US using this method in January, drawing condemnation from the United Nations and the European Union.

An execution by lethal injection is scheduled in Oklahoma on Thursday.

Emmanuel Littlejohn (53) was sentenced to death for the 1992 murder of the owner of an Oklahoma City convenience store during a robbery. Littlejohn has admitted taking part in the robbery but has denied shooting the store owner.

There have been 13 executions in the US this year – three in Alabama, three in Texas, two in Missouri, two in Oklahoma, and one each in Florida, Georgia, and Utah.

The death penalty has been abolished in 23 states, while six others – Arizona, California, Ohio, Oregon, Pennsylvania, and Tennessee – have moratoriums in place.