A South Carolina prisoner scheduled to be executed has decided to die by firing squad instead of the electric chair, in what he called a choice of "two unconstitutional methods of execution."

Richard Bernard Moore, 57, is set to be the first man to be executed in the state since 2011, and the first to choose his method of death after a law went into effect last year making electrocution the default. If it goes as scheduled, Moore will be executed on April 29.
Moore has spent more than two decades on death row after being convicted of killing a convenience store clerk in 1999 in Spartanburg, South Carolina.
"I believe this election is forcing me to choose between two unconstitutional methods of execution, and I do not intend to waive any challenges to electrocution or firing squad by making an election," Moore said in a written statement, according to the Associated Press.
Moore's lawyers are asking the state to delay the execution so the U.S. Supreme Court can review whether his death sentence was a disproportionate punishment compared with similar crimes. The state justices denied a similar appeal last week.

The South Carolina Department of Corrections spent $53,600 to renovate the death chamber to allow the firing squad method. The death chamber now has bullet-resistant glass and a chair in the corner of the room away from the current electric chair.
Three volunteers, all employed by the Department of Corrections, will be behind a wall with the rifles. The inmate will be strapped to the chair with a bag placed over their head.
A small target will be placed over the inmate's heart. Once the warden reads the execution order, the team will fire. Afterward, a doctor will examine the inmate to declare them dead.
During Moore's 2001 trial, prosecutors say he entered a convenience store looking for money to support his cocaine habit and got into a dispute with the clerk. The clerk drew a pistol on Moore, which he wrestled away from him.
The clerk pulled out a second gun, and the two began a gunfight. The clerk shot Moore in the arm, and Moore shot the clerk in the chest, according to court documents. At the time, Moore claimed that he acted in self-defense after the clerk drew the first gun.
South Carolina is one of eight states to still use the electric chair and one of four to allow a firing squad, according to the Washington-based nonprofit Death Penalty Information Center. The other states that allow firing squad execution are Mississippi, Oklahoma and Utah.
Only three executions in the U.S. have been carried out by firing squad since 1976, according to the center.
Newsweek reached out to Moore's attorney for comment.