The South Carolina Supreme Court has rejected the final appeal of Brad Sigmon, clearing the way for his execution by firing squad on Friday.

Sigmon, 67, convicted of beating his ex-girlfriend’s parents to death in 2002, chose the firing squad over lethal injection, citing concerns over painful execution methods and a lack of transparency regarding the state’s lethal injection drugs.

His lawyers argued that his original trial defense was inadequate.

Sigmon will be the first U.S. inmate executed by firing squad in 15 years, the Associated Press has reported.

He also plans to seek clemency from Governor Henry McMaster before the execution.

Written by B.C. Begley