Mater Dei High School‘s former dean of students was arrested by Middletown police Tuesday on sexual assault charges.

Police say William Miltner, who worked at the school for four years and was promoted to the dean’s post last year, sexually assaulted a student in 2009.

Twenty-eight-year-old Miltner, of Middletown, was charged with second-degree aggravated sexual assault and fourth-degree aggravated sexual contact.

Police said in 2009, Miltner, who was also a teacher and soccer coach at Mater Dei, had an “ongoing sexual relationship with the student which occurred outside of school in April of 2009.”

The student, then 16, has since graduated and is now 18 years old, Detective Lieutenant Steve Dollinger said in a release.

The Asbury Park Press, citing court documents reports further:

The incident allegedly occurred on April 20, 2009, the court documents reveal.

First Assistant Monmouth County Prosecutor Chris Gramiccioni declined to release the name of the minor, citing the victim’s age.

The Catholic high school is part of the Diocese of Trenton. Diocese spokeswoman Rayanne Bennett said in a statement e-mailed to the Asbury Park Press that Miltner is no longer employed by the school.

According to a Mater Dei newsletter, Miltner is a 2000 graduate of the school and was hired as an English teacher in the fall of 2007.

“William Miltner was the subject of an anonymous e-mail that was sent to the leadership of Mater Dei Prep,” the statement said. “Due to the nature of the e-mail, the information was forwarded to the county prosecutor’s office in accordance with school and diocesan policies. ”

The statement says the diocese is “cooperating fully with the law enforcement process.” Bennett also noted all teachers employed in diocesan schools have undergone criminal background checks.

Miltner is being held in the Monmouth County Correctional Facility in Freehold on $125,000 bail with no 10-percent option.