Jacob Christian Muse, of College Park, is charged with three counts of malice murder, the Georgia Bureau of Investigation said in a Friday release.
Last week's crime left three members of a family dead at the rural Coweta County's Lock Stock & Barrel Shooting Range.
Grantville officers discovered the bodies of the gun range's owner, his wife and grandson on the evening of April 8
Police Chief Steve Whitlock said investigators believe the shooting occurred around 5:30 p.m., when the range normally closes.
The victims – who were found shot to death inside of the family business – were identified as Thomas Hawk Sr., 75, Evelyn Hawk, 75, and Alexander Luke Hawk,17.
Investigators said that as many as 40 guns and the range’s surveillance camera were stolen at the same time.
"We’re just a small town, 12 officers. I’ve been here eight years and have never had to investigate anything like this. It’s been kind of hard on us. The crime rate is really, really low," Whitlock said.
The Georgia Bureau of Investigation (GBI) noted that crime scene specialists spent days documenting, collecting and preserving evidence, turning over physical evidence to Bureau of Alcohol, Tobacco, Firearms and Explosives and GBI crime labs.
Whitlock said the Hawk family was well-known and well-respected in their community and had operated Lock Stock & Barrel for nearly 30 years.
Their grandson – the son of Coweta County's coroner – was on spring break and helping his grandparents at the shop.
Coweta County Sheriff Lenn Wood wrote on Facebook that the "Hawk Family, the City of Grantville and the Coweta Community were forever broken and changed by the senseless and tragic event that happened in Grantville."
Officials said Muse was booked into the Coweta County Jail – though authorities did not release additional information about his arrest and it was not immediately clear whether Muse had an attorney who could comment.
Fox 5 Atlanta reported that the joint investigation into the murders remains open and very active and that police said someone had taken a camera DVR from the business.
The station noted that there was a combined reward of $25,000 for information leading to an arrest and conviction, though it was not immediately known if anyone will be claiming the money.
Fox News' Danielle Wallace and The Associated Press contributed to this report.