(NEXSTAR) – Law enforcement officials in Georgia have arrested a 21-year-old man in connection with a triple homicide and robbery at a gun range in Grantville last week.

Jacob Christian Muse of College Park has been charged with three counts of malice murder, the Georgia Bureau of Investigations, the ATF and the Grantville Police Department announced in a joint statement on Friday.

Just one week earlier on April 8, police in Grantville responded to the Lock, Stock & Barrel Shooting Range at about 8 p.m., where they found the bodies of the range’s owner, his wife and their grandson. Officials later identified the victims as Tommy Richard Hawk Sr., 75, Evelyn Hawk, 75, and Alexander Luke Hawk, 17.

Police in Grantville said the teen had been helping out at his grandparents’ business during spring break.

“This is just a shock to everybody in the community,” Police Chief Steve Whitlock told the Associated Press, adding that the Hawk family business was a fixture in the town for three decades. “We’re trying to do the best that we can to figure this out.”

The range had also been robbed of “approximately 40 weapons” and a digital camera, the Grantville Police Department wrote on Facebook.

Due to the nature of the crime and the theft of the weapons, the Georgia Bureau of Investigation and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) were called in to work the case. The sheriff’s department in Coweta County had also assisted, Grantville Police confirmed.

Muse was booked into the county jail on Friday. Authorities said the investigation remains active.

The Associated Press contributed to this report.