Cherry Hill Police say two men exchanged gunfire outside a room at the America's Best Value Inn around 12:02 a.m. Friday.
By the time police got there, they say those two were gone.
Authorities say interviews of witnesses did not develop "conclusive information."
At least six shell casings were found in the parking lot and one bullet was found inside an apartment in an adjacent complex.
Two men at the party were arrested on outstanding warrants in unrelated cases.