SCOTTSDALE, Ariz. -- A substitute teacher and assistant track coach in the east Valley is under arrest, accused of sexually abusing a student, Scottsdale police say.

He is identified as Tom Porras, 49, of Scottsdale.

The School Resource Officer at Saguaro High School was notified by the school staff on Thursday of an alleged incident involving Porras and a 17-year-old student, officers said.

According to court paperwork, Porras invited the girl to his house to give her an athletic massage and watch videos of other athletes participating in the long jump. Porras allegedly told the girl to bring a swim suit and workout clothes.

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The girl said she trusted Porras because other athletes had gone to his house for massages and workouts before. She said she also trusted him because Porras is a personal trainer.

According to court paperwork, the girl changed into her swimsuit and Porras engaged in unwanted sexual contact with her.

Scottsdale police said they interviewed and then arrested Porras on suspicion of sexual abuse on Thursday afternoon.

During interviews, Porras made admitted to touching himself and the girl, court paperwork shows.

Porras was released under supervision on an electronic monitoring program.

CBS 5 investigated his background and learned Porras was a quarterback in the Canadian Football league for more than a dozen years.

He is married with a son and has worked for Saguaro High School since 2003.

This is the second time this school year that an adult has been arrested for a sex crime against a student at Saguaro High School.

In August, a school janitor was charged with raping a 14-year-old student.