South Carolina will execute Freddie Owens on Friday. What you need to know.

The execution of a death row inmate for killing a single mother of three in South Carolina could be the first in the state in more than a decade and the 14th in the United States this year, even though a key witness who testified against him has since proclaimed his innocence.

Freddie Eugene Owens, 46, is scheduled to be executed by lethal injection at 6 p.m. Friday. He was convicted of murdering 41-year-old Irene Grainger Graves, who was shot in the head during a Halloween night robbery at the supermarket where she worked in 1997.

On Wednesday, Steven Golden, Owens' co-defendant in the robbery, signed an affidavit stating that Owens did not shoot Graves and was not even there that night, the Greenville News, part of the USA TODAY Network, reported.