GRASS VALLEY (CBS13) — An alleged fight club on a high-school campus has parents demanding action from the school district after videos were posted on social media, and an article describing them surfaced on YubaNet.

The violent fights allegedly happened in a baseball clubhouse at Nevada Union High School. They reportedly happened during school hours, but school officials say they only learned about them when a parent showed them a video.

In a video, you can see the fighters wearing boxing gloves. Two students take cellphone video and one fighter appears to be wearing a baseball uniform. The fight is brutal and violent with one person punched straight on the face. There is no headgear, no helmets.

Yet, students are laughing throughout the video.

Parents we spoke with are outraged at the videos saying they have learned the fights have been going on for months.

“A parent contacted us concerning that she had found a video that appeared to be students fighting on school premises,” said Superintendent Louise Johnson.

The district says when it learned of the fight club and saw the videos earlier this week, it took action.

“We immediately opened an investigation. We’ve shut down the location where the fight took place,” she said.

The place is allegedly in an old dilapidated baseball clubhouse where students say fighters tumble into chunks of drywall, tools and equipment on the floor.

So how did this so-called fight club go on in a building on campus during school hours right under the noses of school personnel?

Some parents find that hard to believe.

“High-school administration is investigating the student part of it and superintendent’s office is investigating whether there is any personnel involved,” Johnson said.