THE BRONX - A former math teacher at the prestigious Riverdale County School has been charged with having sexual encounters with a student, according to police.

Richard Hovan, 30, pleaded not guilty to charges of criminal sex and child endangerment after authorities say he had at least two encounters with the teenager.

Investigators say Hovan began texting and emailing the girl when she was 15 years old, and in April and May of 2011, he had two sexual encounters with her after she turned 16.

Officials say Hovan was fired last May after the school learned about the allegations. The head of the school, Dominic Randolph, said in a statement, "Throughout this yearlong process, we have attempted to address this situation in a way that protects the affected family and our students."

Hovan is currently free on $25,000 bond and is working as a private tutor.