A seventh man has been charged in an alleged slashing that took place at a high school graduation on the Hofstra University campus, according to the Nassau County District Attorney's Office.

Michael Gaines, 21, and the previous named six alleged accomplices, all pleaded not guilty to the June attack.

Prosecutors say the men also punched, kicked and stomped on the alleged adult male victim as the graduation at The Mack Center was ending. They say a student was also slashed in the ear when he tried to stop the attack.

If convicted, all seven suspects face up to 15 years in prison.