Eleven high school lacrosse players in Syracuse, N.Y., turned themselves in to the authorities on Wednesday in a hazing incident involving younger teammates that the district attorney said included a gun and a knife.

William J. Fitzpatrick, the district attorney for Onondaga County, had given the players 48 hours to surrender and turn in the gun or face criminal kidnapping charges.

He called the episode “hazing on steroids,” and said the students would be charged with unlawful imprisonment, a misdemeanor.