The Dutchess County Sheriff's Office says the incident took place immediately following a football game at Arlington High School in LaGrange around 9 p.m.
A 16-year-old Arlington student stabbed and taken to Mid-Hudson Regional Hospital where he was pronounced dead.
Police arrested 18-year-old Poughkeepsie resident Nestor Ortiz-Ocampo.
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He has been charged with manslaughter in the first degree.
An arraignment was planned for Saturday.
Police say Ortiz-Ocampo was a former student at Arlington High School.
The Superintendent of Schools Dr. Dave Moyer sent a letter to families and students on Saturday.
"It is with deep sadness that we inform you that an Arlington High School student was stabbed and later died from his injuries following Friday night's football game," Moyer said in the letter.
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He says a crisis team will be available in the Arlington High School library from 12:00 p.m. until 3:00 p.m. on Saturday to assist students, staff and community members affected by the tragic incident.
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