Matthew Pleasonton, 30 of Middletown, Delaware was arrested on Monday and faces more than 20 charges.
Police say it was on January 25th when officers were contacted by administrators at Glasgow High School in Newark for a report that a male teacher was involved in a sexual relationship with a 17-year-old female student.
Investigators say they learned the relationship began back in September, 2011.
Pleasonton was charged with Continuous Sexual Abuse of a Child, Sexual Abuse of a Child by a Person of Trust First Degree (10 Counts), and?Unlawful Sexual Contact Second Degree with Person less than 18 years of age (10 counts).
Pleasanton was arraigned on the charges and released after posting $112,500 Secured Bond.