An alleged member of the Hells Angels was charged with killing another biker during fighting at a motorcycle and tattoo expo called the Hellraiser Ball.
More than 70 people were in custody. At least 10 others were injured at the event in Plainview, four by gunfire.
Saturday's violence was the latest in a feud between the Hells Angels and the Pagans gang, said Nassau County Chief of Detectives Herbert Faust.
Authorities charged Raymond G. Dwyer, 38, of Oceanside with the murder of Robert Rutherford, 51, a purported Pagan member.
