Mikal Mahdi shot his victim nine times before setting him on fire.
The 42-year-old will be executed tonight. The cop-killer is to be executed at 6pm (10pm UK time) at a prison in state capital Columbia for the murder of 56-year-old police captain James Myers.
Myers was shot nine times after he found Mahdi hiding in a shed on his property. Mahdi then set his body set on fire.
Mahdi also pleaded guilty to murdering a convenience store clerk three days before he killed Myers.
South Carolina gives Death Row inmates a choice between lethal injection, the electric chair or the firing squad.
Mahdi chose the firing squad, which is an uncommon choice and only the fifth time a prisoner was executed by firing squad in the US since 1976, with the other four happening in Utah.
The first execution by firing squad in the United States in 15 years was carried out in South Carolina on March 7, when a man convicted of murdering his ex-girlfriend’s parents was put to death.
When Mahdi was four years old his mother fled her abusive husband and the boy was raised by his volatile mentally ill father, they said.
‘Between the ages of 14 and 21, Mikal spent over 80 percent of his life in prison and lived through 8,000 hours in solitary confinement,’ his lawyers said.
