A former math teacher at a prestigious city high school has been charged with having sexual encounters with a 15-year-old student.

Richard Hovan pleaded not guilty Monday to criminal sex act and child endangerment charges. Defense lawyer Vinoo Varghese says the former Riverdale Country School teacher denies the allegations and is looking forward to clearing his name.

The Manhattan district attorney's office says the encounters happened at Hovan's apartment last year.

The school says it fired Hovan quickly after learning about the allegation last May.

He was in his first year of teaching at the private school in the Bronx. Alumni include the late Sen. Edward M. Kennedy.

Varghese says the 30-year-old Hovan is now working as a private tutor. Hovan is free on $25,000 bond.

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