HOCKESSIN, Del. (CBS) —  State Police in Delaware say a former choir director has been charged with raping a female student at H.B. DuPont Middle School.

Authorities say 43-year-old Gary Smith, of Newark, began a sexual relationship with a then-13-year-old girl in April 2010.  The relationship continued until August 2012.  Throughout that period, sexual offenses were allegedly committed on school grounds numerous times.

Police say a two-month long investigation into the allegations began in early September after receiving a tip that a rape occurred at the school.

Smith was arrested at his home Tuesday morning.  He’s been charged with 27 counts of 3rd Degree Rape and Continuous Sexual Abuse of a Child, as well as other offenses.  After his arraignment, Smith was detained in lieu of $815,000 bond.

Police said questions regarding Smith’s status with H.B. DuPont Middle School should be directed to the Red Clay District Office.

Anyone with information about Smith is asked to contact police at 302-365-8567.