FORT LAUDERDALE (CBSMiami) – A teacher at Cardinal Gibbons High School has been arrested and faces 20 counts of unlawful sexual activity with minors for a sexual relationship with a student.

According to the arrest report, John Farrell, 25, started the consensual relationship with the girl during after-school activities. Police said the two would leave school and go to Farrell’s home where they would have sex.

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Police said a controlled phone call between the victim and Farrell ended with the math and statistics teacher acknowledging the ongoing relationship. Farrell also asked the girl not to say anything about the relationship.

Farrell is being held on bond which was set at $50,000.

Cardinal Gibbons High School confirmed that Farrell has been a teacher there for one year and went through the background screening process required of new teachers.

Sophomore Matty Ryan said Farrell was his statistics teacher last year.

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“It’s been kind of crazy to think someone who taught you would do something like that,” Ryan said. “I also know the girl and she didn’t seem like someone who would do something like that.”

Parents reacted with anger after the arrest was made.

“It makes me sick, being a teacher around kids you have responsibility to the kids and adults, everybody, it’s sickening,” said parent Jeff Palolillo.

“I live in Parkland and send my daughter here and to have this happen to my daughter when I pay full tuition is disturbing,” said parent Camille Mucci.

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Cardinal Gibbons said in a statement, “Mr. Farrell is on unpaid administrative leave pending the outcome of the investigation.”