"This is just a shock to everybody in the community," Whitlock told Associated Press. "We're trying to do the best that we can to figure this out."
Whitlock said investigators believe the robbery and shooting happened around 5:30 p.m. Friday, which is when the range normally closes. He said Hawk's son, Richard, came by the business and was the person who found the victims.
There are no suspects as of early Saturday, and no arrests have been made, he said. Investigators said that as many as 40 guns and the range's surveillance camera were also stolen.
The Georgia Bureau of Investigation is investigating, but when contacted today referred all inquiries to Grantville Police. The Bureau of Alcohol, Tobacco, Firearms and Explosives was also called in due to the amount of weapons taken. Whitlock said he's grateful for the help from other law enforcement agencies in the investigation.
"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," he said.
A reward of $15,000 has been posted for information leading to the arrest and conviction of the killer or killers in the case, according to the ATF Atlanta office's Twitter feed.
"ATF and our law enforcement partners will work tirelessly to bring the killer(s) to justice," ATF Atlanta Field Division Special Agent in Charge Benjamin P. Gibbons said in a statement. "The brutality of these senseless murders along with the fact that these killer(s) have acquired additional firearms makes solving this case our top priority."
A message left with the ATF office in Atlanta was not immediately returned.
Police are asking any witnesses to come forward. Whitlock said they don't have any video evidence to work with right now.
"Anyone having driven by the shooting range during the time frame of 530pm to 630 pm that may have seen vehicles other than a white Ford dually truck and a black Ford expedition are asked to contact the police department," Grantville police said in their Facebook statement.
The shooting range is in rural Coweta County, about 50 miles (about 80 kilometers) southeast of Atlanta.
- Associated Press writer Chevel Johnson reported from New Orleans.