MEDIA, P.A., (CBS) – According to the Delaware County District Attorney, a teacher in Media, Pa was arrested for his relationship with an 18-year-old student at Ridley High School.

Authorities say Gregory A. Stanczuk, a physics teacher and track and field coach at the high school, was charged with institutional sexual assault, a felony of the third degree.

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His arrest comes at the conclusion of an investigation conducted by Sgt. Robin F. Clark of the Delaware County District Attorney’s Criminal Investigation Division Child Abuse Unit, according to police. Police say on January 29, Sgt. Clark received information about the sexual assault of a former student at Ridley High School by Stanczuk, a physics teacher of more than 30 years and head girls track and field coach.

According to police, the female victim told them, Stanczuk was her track and field coach during the four years she attended Ridley High School. He was also her teacher freshman year. According to the victim they spent a lot of time together and became close emotionally during her senior year when she broke up with her boyfriend.

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The victim allegedly told police that their relationship evolved and he allegedly performed sexual acts on the victim, according to the district attorney’s office.

“As a teacher and coach, Gregory Stanczuk flagrantly used his position of trust and authority to exploit the victim, manipulating her emotionally for his own sexual gratification,” said District Attorney Jack Whelan.

Authorities say he crossed the line between teacher and student and committed a crime by engaging in sexual behavior with his student.

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Police are asking any parent that feels their child has been victimized to contact Sgt. Clark at 610-891-4118.