A South Carolina death row inmate who gruesomely killed his ex-girlfriend’s parents with a baseball bat in 2001 is scheduled to be executed by firing squad on Friday – the first execution of its kind in the U.S. in 15 years.

Brad Sigmon, 67, who admitted to the killings because his ex-girlfriend refused to get back to him, will be strapped to a chair at around 6 p.m. and three volunteers armed with rifles about 15 feet away will fire bullets into his heart.

Each will be armed with .308-caliber, Winchester 110-grain TAP Urban ammunition often used by police marksmen. The bullet is designed to shatter on impact with something hard, like an inmate’s chest bones, sending fragments meant to destroy the heart and cause death almost immediately.

Brad Sigmon will be put to death by firing squad Friday. (Kinard Lisbon/South Carolina Department of Corrections via AP, left, South Carolina Department of Corrections via AP, right.)

“My intention was to kill her and then myself,” Sigmon said in a confession typed out by a detective after his arrest. “That was my intention all along. If I couldn’t have her, I wasn’t going to let anybody else have her. And I knew it got to the point where I couldn’t have her.”

Five states — Idaho, Mississippi, Oklahoma, South Carolina and Utah — authorize the use of firing squads in certain circumstances.

Just three inmates — in Utah in 1977, 1996 and 2010 — have faced a firing squad in the U.S. since the death penalty was reinstated in 1976. Ronnie Gardner was the last prisoner to be executed by firing squad, in Utah in 2010.

This 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)

Executions in South Carolina resumed in September, when the state – once one of the busiest for executions – ended a 13-year pause in carrying out the death penalty.

The pause was caused in part by the state having difficulty obtaining lethal injection drugs after their supply expired because of pharmaceutical companies’ concerns that they would have to disclose they had sold the drugs to state officials. The state legislature then passed a shield law allowing officials to keep lethal injection drug suppliers private.

Twenty-five executions were carried out in the U.S. last year. Five have already been carried out in 2025, per the Death Penalty Information Center.

Fox News’ Landon Mion and The Associated Press contributed to this report.