CHARLOTTE, N.C. -- We send our children to school each day, never expecting their own classmates to be predators. But, a year-long investigation by the Associated Press uncovered thousands of students were sexually assaulted by their peers.

The AP examined state education records and federal crime data and discovered roughly 17,000 official reports of sexual assaults by students over a four-year period, from 2011-2015.

The study found that student-on-student sexual assaults were more common than teacher-student assaults. For every adult-on-child sexual attack at school, there were seven assaults by other students.

The data revealed that students are most likely to become targets at home and at school. Many places without supervision became prime spots for the attacks: locker rooms, busses, bathrooms, and playing fields.

Advocates who work with sexual assault survivors in Charlotte suspect the number is much higher, saying many crimes often go unreported, particularly by children.

“Threats, fear, being ashamed, wanting to belong,” says Ann Glaser, Director of Program Services at Pat’s Place Child Advocacy Center. “School is their world. Home and school. That’s it. And if they don’t belong there, they don’t feel they belong anywhere.”

Glaser says many students worry about getting in trouble or not being believed.

“There’s a big, big fear of not being believed,” Glaser says. “Adults, especially if they haven’t experienced something like this themselves, don’t want to believe that something like this could happen.”

The AP investigation also shines a light on the adults who cover up, downplay, or misclassify incidents as “hazing.”

Many of the documented incidents involved sports teams.

Local schools have seen several high-profile incidents in the past five years.

At McDowell High in 2015, a student claimed he was sodomized with a broomstick, enough to cause serious injuries. At the time, a law enforcement spokesperson downplayed it as “teenage, teammate, hijinks.” Students at the school claimed the incident with the broom was a “ritual” that has been going on for years.

At Clover High School in 2011, similar allegations by three football players about attacks in a locker room led to 13 kids being suspended.

A former college player who now coaches says hazing happens on every level, to varying degrees.

“It’s sad in a lot of ways, just because everyone doesn’t deserve that kind of treatment,” says Vincent Jacobs, who now runs a high school combine in Charlotte.

He says the tone is set from the top, stressing the importance of open relationships, and clear communication of expectation between coaches and players.

“It has to be zero tolerance,” he says. “There’s so many things that youth sports guys deal with. This is just another thing that we make sure we make a topic of conversation.”