FILE - This undated photo provided by the South Carolina Department of Corrections shows the state's death chamber in Columbia, S.C., including the electric chair, right, and a firing squad chair, left. (South Carolina Department of Corrections via AP, File)

This photo provided by South Carolina Dept. of Corrections shows Richard Moore, who was sentenced to death in the September 1999 killing of convenience store clerk. ( South Carolina Dept. of Corrections via AP)

This undated photo provided by the South Carolina Department of Corrections shows the witness room in the execution chamber at the Broad River Correctional Institution in Columbia, S.C. (South Carolina Department of Corrections via AP)

This undated photo provided by the South Carolina Department of Corrections shows the execution room at the Broad River Correctional Institution in Columbia, S.C. (South Carolina Department of Corrections via AP)

This photo provided by Justice 360 shows death row inmate Richard Moore at Kirkland Reception and Evaluation Center in Columbia, S.C., Aug. 17, 2018. (Justice 360 via AP)