CHESTERFIELD, Va. (AP) -- Police say a 20-year-old man was killed and seven other young people were injured after gunfire erupted during a graduation party in Central Virginia.

Two separate fights between attendees of the mostly outdoor party in Chester were reported shortly before police received a call about shots fired Friday night.

Chesterfield County Police gave an update on their investigation Saturday.

Police say it isn't immediately clear how many shooters were involved in the gunfire. But officers recovered more than 50 casings of four different calibers.

Of the injured, five were shot and two were struck by a vehicle while fleeing the shooting. No arrests have been announced.