South Carolina's first firing squad execution will involve a target, volunteer shooters and special bullets

When a South Carolina man who killed his ex-girlfriend's parents with a baseball bat steps into the death row chamber Friday night, it won't be lethal injection or electrocution that ends his life.

It will be three people holding rifles about 15 feet away who will complete his punishment in what will be the United States' first firing squad execution in 15 years.

Some 46 prisoners have been executed by lethal injection and electrocution in South Carolina since 1985. Brad Sigmon's execution will be the first by firing squad. 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.