A man claiming he endured sexual abuse as a student filed a federal lawsuit against Indian Mountain School in Lakeville on Thursday. It’s the third such suit filed against the private boarding school in less than two years and the latest in a long line stretching back more than 20 years.

New York resident Matthew Bernstein says in his suit that he was sexually abused by teachers while a student at the private boarding school from 1980 to 1983. Much of his claims focus on Christopher Simonds, a teacher who has been named in the previous suits and was the subject of a 1992 State Police investigation.