A Minnesota father called out his daughter's bullies in an emotional and explicit video posted on YouTube this week.

Brad Knudson is white, and has an adopted African-American daughter. When he found out she was being taunted on social media site Snapchat, he sprang into action.

"With Snapchat, you hold the button down when you receive [the message] or view it, and then it disappears," he explained. His daughter's friend informed him that there were classmates sending his daughter bullying messages, so he used his cell phone to record the videos.

In the video messages, a male and female student called his daughter a "slut," a "fat [expletives]," and used the n-word. Knudson identified the pair as twin siblings.

"I found out who these kids were, I attempted to call the twins' parents, left multiple messages, never got anything back," he reported. "Went to their house numerous times, no one ever answered the door."

Knudson said he went to the police because friends of his lost their 13-year-old son to suicide after the teen was bullied.

"I can't have this hanging over us, and our daughter thinking the worst, and something could happen," he said.

The police contacted security officials at his daughter's school, and called the offending students into the office. Knudson was then able to speak to the children's father on the phone, and got a surprising reaction from the man.

"He told me that I was crazy, that that's what he did when he was a kid, and that he and his family make jokes at the house using [the n-word] all the time, so what was the big deal," Knudson alleged. "I said a few things to him that I can't repeat in this video."

The twin's father allegedly left him a disparaging voicemail in return, and called him a "[expletive] lover."

Knudson was incensed.

"I called him back and I said, 'Yeah, that's a correct statement,'" he recounted. "'I am an n-lover because I have a beautiful African-American daughter who I love more than life itself, and would do anything for her.'"

He went on to reveal the father's name, and dbTechNo reported that the man lost his job. Knudson said he was just trying to protect his daughter.

"I love my daughter, and I don't want her to end up committing suicide," he said.