Washington DC - A man convicted of the 2004 murder of an off-duty police officer is to be put to death by firing squad Friday in South Carolina, the second such execution in the state this year.

Mikal Mahdi (42) is to be executed at 6:00 PM ET at a prison in state capital Columbia for the murder of James Myers.

Myers, a 56-year-old police captain, was shot nine times after he found Mahdi hiding in a shed on his property. His body was then set on fire.

Mahdi also pleaded guilty to murdering a convenience store clerk three days before he killed Myers.

Justice Mikal Mahdi put to death by firing squad in South Carolina

South Carolina gives Death Row inmates a choice between lethal injection, the electric chair, or the firing squad. Mahdi chose the firing squad.

The first execution by firing squad in the US 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.

A three-person squad of Department of Corrections volunteers opens fire on the condemned man, who is restrained in a chair with a hood over his head 15 feet away.

Mahdi has requested clemency from Governor Henry McMaster, but South Carolina's Republican chief executive has not granted any previous clemency petitions.

"Mr. Mahdi's life is a tragic story of a child abandoned at every step," his lawyers said in a statement.

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% of his life in prison and lived through 8,000 hours in solitary confinement," his lawyers said.

"Now 42, Mikal is deeply remorseful and a dramatically different person from the confused, angry, and abused youth who committed the capital crimes."

There have been 11 executions in the US so far this year. There were 25 last year.