A double shooting outside an Athens home that killed a 16-year-old boy and a Hall County man this week stemmed from an attempted dirt bike sale, investigators said Friday.

The incident happened Monday afternoon in the Stonehenge subdivision off Atlanta Highway, authorities said previously. According to an incident report, police arrived to find a “large crowd” gathered around two victims on the ground.

Ashawn Adams, 16, of Athens, was pronounced dead at the scene. A second man, 21-year-old Casey Parten of Flowery Branch, was rushed to the hospital with gunshot wounds but died of his injuries two days later, The Atlanta Journal-Constitution previously reported.

On Friday, investigators said Parten and his older brother Tyler Parten drove to Athens after arranging to buy a dirt bike from Adams.

“The sale of the dirt bike was advertised on Facebook Marketplace and all parties agreed to meet at an address in the Stonehenge subdivision,” department spokesman Geof Gilland said.

It’s unclear what happened next, but the meet-up ended in an exchange of gunfire, authorities said. Two guns were recovered from the scene, but investigators are still working to determine what led to the shooting, Gilland said. It wasn’t immediately clear if officers recovered a dirt bike from the scene.

“We’re waiting on the results of the autopsies and evidence testing to determine who shot who,” Gilland told the AJC.

The investigation is ongoing, but detectives are looking to speak with anyone who may have responded to the Facebook listing for a dirt bike in the Stonehenge neighborhood. The department also said that meeting strangers to buy or sell expensive items is “inherently risky.” Those arranging in-person sales with strangers are encouraged to meet in well-lighted, highly populated public areas or outside Athens police headquarters, where there is 24-hour surveillance.

Anyone with information about the case is asked to contact Detective Paul Johnson at paul.johnson@accgov.com or 762-400-7060.