PLANO, Ill. (CBS) –Five students at southwest suburban Plano High School are accused of sexual assault and battery over possible hazing incidents.

A Plano High School parent says her child told her a Plano athlete attacked a friend in a locker room months ago.

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“It’s very upsetting. I was mortified,” the parent said.

Back in February the mother of a 15-year-old Plano basketball player told police team members sexually assaulted and battered her son in the boys’ locker room, sodomizing him with their fingers.

The mom filed a civil lawsuit against Plano School District 88. After a seven month investigation, two football players reported it happened to them in 2012 and that it was considered part of team membership.

“It wouldn’t meet the legal definition of what we consider hazing, but it’s as close as you can come,” said Eric Weis, Kendall County State’s Attorney.

Five Plano High School students face criminal charges, including criminal sexual assault, aggravated battery and unlawful restraint.

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“Four of them have been charged with the holding down of the victims. Each one of them was involved in one incident,” said Weis.

Investigators believe the fifth suspect penetrated all three victims.

Students say to many, assaults are part of team culture.

“I’ve seen it happen a couple of times and I just left the locker room,” said one student.

The school’s principal says the cases prompted them to beef up security.

“It’s been important that we have practices in place for our coaches and teachers to make sure that they’re definitely in the locker rooms and actively supervising,” said Eric Benson, Plano High School Principal.

All five suspects were released to parents and they all face strict limits on their movement. Each was ordered to have no contact with the victims, and all are subject to curfews and home confinement. Kendall County State’s Attorney Eric Weis says the student facing the most serious charges has been put on a GPS monitor.

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A student safety hotline will be available starting Thursday at (630) 552-7290 so students can report cases of bullying.