KENNESAW, Ga. — Investigators have identified three men found shot to death on the golf course of a country club in the Atlanta suburbs, but it’s still unclear what prompted the violence.

Golf pro Eugene Siller was gunned down when he went to find out why a white pickup truck had driven onto the 10th green at Pinetree Country Club in Kennesaw on Saturday afternoon, police said.

Two other men — both fatally shot — were then found in the bed of the pickup truck. Cobb County police on Wednesday identified those men as 46-year-old Henry Valdez of California and 76-year-old Paul Pierson of Kansas.

The gunman is believed to have gotten away on foot, authorities said. He remained on the loose Wednesday.

Investigators believe that Siller, 46, was slain because he came upon a “crime in progress,” police have said. It doesn’t appear that he was targeted, and the other men appear to have “no relation to the location at all,” police said in a statement. Pierson was the truck’s registered owner.

Police haven’t commented on any possible motive for the killings of the two men whose bodies were found in the pickup.

The country club is near the campus of Kennesaw State University, about 25 miles northwest of downtown Atlanta.