MINNEAPOLIS (WCCO) — A student’s secret recordings have kept a Minnesota teacher out of his classroom while a school district investigates.

For months, the seventh-grade science teacher at Hibbing High School can be heard on cellphone video insulting and degrading students, from rants about their intelligence, to their looks.

“That’s number 12. That’s where we’re going to start 15 minutes later. Dipstick,” Dan Gotz is heard on a recording saying.

On a different day he said this: “You build them up in the little muscle cells that you have, but in [his] case, not a whole lot of it. Scrawny little toothpicks hanging out of his shirt.”

Even their family.

“You’re a good kid could you please stay that way? Smart, responsible … then there’s that thing,” Gotz said. “Your mom and dad had a bad day or something on that day.”

Hours of iPhone recordings seem to suggest nothing is off limits for Gotz in his class filled with 12 and 13 year olds.

“This is my room. I’m telling you what to do and until you get it through your head I’m telling you what to do in here!” Gotz said.

Education attorney Meg Kane represents the families who just came forward after realizing what was happening.

“I was just shocked,” Kane said.

A student grew tired of listening to the insults, and went to work for weeks to prove it.

“You wonder why you bug the living crap out of people,” Gotz said.

“This seventh-grade young man recognized how inappropriate this was, was so offended by it and even though he wasn’t the subject, he had the courage to record those things,” Kane said.

Kane sent a letter to the Hibbing School District detailing what she calls a “pattern of verbal and emotional abusive remarks” — including this one about a mother’s supposed true feelings.

“She might tell you she loves you, but deep in her soul she does not for having a son like you. She is crying on the inside,” Gotz said.

The letter asks the superintendent to immediately “remove Mr. Gotz from teaching responsibilities” for this “outrageous and offensive misconduct.”

“He routinely refers to students as idiots and dipsticks,” Kane said. “This was pervasive, this was persistent.”

Gotz was placed on paid administrative leave last week. When he didn’t call us back, we stopped by his house where he told us he would have no comment. The district said due to privacy laws it would have nothing else to add.

But Kane and the parents can’t help but wonder what months of listening to the attacks will do.

“They barely know themselves, and to have that kind of message drip, drip, drip into their heads is really highly problematic in my opinion,” she said.

Like this exchange with a student about the likelihood he’ll be in summer school.

“June, part of July, go to school from 8 to noon every day while it’s nice and sunny out,” Gotz said. “I’ll drive by and wave at you from the street. I might even honk my horn.”

A student reported Gotz months ago. His parents say the vice principal then observed Gotz for a day only to tell them that he was a “great teacher.”

“Children have to come first, and that isn’t the case in this situation,” Kane said.

In her letter, Kane offers to let the school district listen to the recordings. She says she has yet to hear back from them.