Investigators were trying to determine who tossed a beer keg into a burning barrel at a party, causing a deadly explosion that sent metal shards slicing through a crowd of people.

The explosion early Sunday killed Sean M. Caselli, 22, of New Milford. Seven other people were taken to hospitals with burns and shrapnel wounds, police said. Caselli was struck in the neck by a piece of flying metal.

Sgt. Lee Grabner said investigators interviewed witnesses Sunday to try to identify the person witnesses say threw a quarter-keg of beer into the flames, and to determine whether criminal charges should be filed.

Fires had been set in several barrels to keep people at the partygoers warm at the outdoors party in western Connecticut, said Police Captain Michael Mrazik.

"This is a certain tragedy," said Police Chief Colin McCormack. "However, nothing I have been apprised of to this point in this investigation, which I caution is at the very early states, indicates a deliberate act on anyone's part."