A convicted double murderer in South Carolina became the first American death row inmate to die by firing squad in 15 years — and his execution was the first of its kind to be performed in the Palmetto State.

Brad Sigmon, 67, was pronounced dead at 6:08 p.m. after three state corrections department volunteers armed with rifles lined up behind a wall about 15 feet away and fired off shots at a target on the hooded killer’s heart at 6:03 p.m., according to the Post and Courier.

Sigmon, who was convicted of bludgeoning his ex-girlfriend’s parents, David and Gladys Larke, to death with a baseball bat in 2001, personally chose the violent punishment over the electric chair or lethal injection. 

AP

He became the fourth inmate in the US to be put to death by the unusual method since 1976.

A crowd of protesters gathered outside Broad River Correctional Institution ahead of the execution, according to social media footage.

Sigmon chose the firing squad, believing that he’d die a torturous death from lethal injections. 

He was found guilty of murdering his ex-girlfriend Rebecca Barbare’s parents after he forced his way into their home in Greenville County and beat them to death with a baseball bat. 

David, 62, and Gladys, 59, were in separate rooms as Sigmon went back and forth bashing them with the bat.  

The husband’s “skull was basically broken in two,” the court heard during his trial.

He was found guilty of murdering his ex-girlfriend Rebecca Barbare’s parents after he forced his way into their home in Greenville County and beat them to death with a baseball bat.  AP

Sigmon claimed he was forced to choose his violent death, arguing he wasn’t given information about the lethal injection method when he decided how to end his life. AP

He then kidnapped his Barbare at gunpoint, but she escaped from his car — shooting her as she ran but she survived, according to prosecutors. 

Sigmond had been smoking crack cocaine and drinking on the night of the slayings when he told a friend he would “get Becky for leaving him the way she did,” and “tie her parents up,” according to court documents.

In a confession, Sigmon said, “I couldn’t have her, I wasn’t going to let anybody else have her.”

He planned to kill both Barbare and them himself, he later testified to officers. 

The convicted killer was on the run for 11 days before police caught up with him in Gatlinburg, Tennessee. 

Sigmon has since claimed he was forced to choose his violent death, arguing he wasn’t given information about the lethal injection method when he decided how to end his life.

South Carolina law requires death row inmates to select their own method of execution — lethal injection, electric chair or firing squad. If no choice is made, the default option is the electric chair. 

His attorney made a last-minute appeal to save his life, which was rejected earlier Friday by South Carolina’s Supreme Court. 

Republican Gov. Henry McMaster, who had the option to commute Sigmon’s death sentence moments before the execution began, opted to allow the process to proceed.

No South Carolina governor has granted clemency in the 49 years since the death penalty restarted. 

Sigmon, who enjoyed three buckets of KFC as his final meal, which he shared with his death row buddies, is the oldest of the 46 South Carolina inmates who have been executed since the death penalty was restarted in the US in 1976.