DETROIT (AP) — A Michigan professor who was suspended after making a provocative video for his students is threatening to file a lawsuit if Ferris State University doesn’t lift the sanction.

An attorney for Barry Mehler warned the school in a letter Tuesday. Matthew Hoffer says the history teacher is protected by the First Amendment and a contract between Ferris State and its faculty.

Mehler’s 14-minute video at the start of a new term was peppered with profanities and unusual remarks about grades, plagiarism and classroom attendance during the COVID-19 pandemic.

Ferris State President David Eisler says he was “shocked and appalled.”

Mehler has been placed on leave.