DALTON, Ga. (AP) — A 16-year-old has been arrested on murder charges after three men and a 17-year-old boy were found dead in a park near the north edge of Dalton, Georgia, authorities said.

The teenager, from Rome, Georgia, faces four counts of felony murder, Whitfield County Sheriff Scott Chitwood told reporters at a Sunday evening news conference.

Deputies were called to Pleasant Grove Park around 11:15 p.m. Saturday after reports of shots being fired. When they arrived, they found four dead Hispanic males, authorities said.

The victims were two men from Dalton, ages 19 and 21; and two males from Rome, who were 17 and 18.

The motive appears to have been a robbery, possibly involving “some contraband” that was found in a vehicle, the sheriff said. He didn’t elaborate on the nature of the contraband.

“We have absolutely no reason at all to believe it’s gang-related whatsoever,” Chitwood said. “We think it’s sadly just a very isolated incident.”

Multiple weapons were involved in the shootings, based on shell casings recovered at the scene, Chitwood said. He described the case as “very, very complicated” and said detectives were working to learn more about the circumstances.

The park is about 90 miles (145 kilometers) northwest of Atlanta.

The Georgia Bureau of Investigation has been called in to help local authorities.