It’s unclear whether Muse had an attorney as of Friday. He is at the Coweta County Jail, authorities said.
The victims were the range owner, Tommy Hawk, his wife Evelyn — both 75 — and their 17-year-old grandson, Luke, according to officials. They were all shot inside the family business, authorities said.
The bodies were discovered by Coweta County Coroner Richard Hawk, son of the couple and father to Luke, according to the police.
Authorities said the suspect had also stolen a cache of firearms from the shooting range, which is about 50 miles southwest of Atlanta.