A US police officer was fired after getting caught on dashcam video temporarily detaining his daughter and her boyfriend.

The officer was fired after an investigation concluded he 'abused his authority' by pulling over his daughter Katlyn Kovach and her boyfriend Makai Coleman, both aged 18, without cause.

Daftey-Service Director Davn Given told the Chronicle-Telegram:

These actions are not acceptable for members of our Police Department and we felt it warranted immediate dismissal.

In the footage, the officer, named as John Kovach Jr., told Coleman to get out the vehicle because he's "going to jail". When Coleman asks Kovach what for, Kovach responds:

Have a seat in my car. We'll make s**t up as we go.

He then got into an argument with Gloria Morales, who comes out of a home nearby and whose two children were also in the car.

He repeatedly asked Morales if his daughter was inside her home, which she denied and demanded he return with a search warrant.

After accusing Morals of being "disorderly", he said he would give her daughter - who was sitting in the front seat - a $300 ticket for allegedly not wearing her seatbelt.

When Morales said she would call 911, he threatened to arrest her, according to documents about the firing, and tells her that Coleman was "harbouring" his daughter.

Eventually, Kovach notices his daughter in the back seat. He tells Coleman to leave the police cruiser. As he pushed his daughter into the car, she cried:

You can't take me, I'm 18.

In the back seat of the police car, his daughter insisted she was not suicidal. He then gets into the cruiser and drives away.

Kovach allegedly told officers he was worried after his ex-wife alerted him to concerning Facebook posts by Coleman about their daughter, though this was later disputed by his ex-wife, and that he believed his daughter was suicidal.

He said he had tracked his daughter's computer to the Morales' home so he waited there for Coleman's car. When the car turned up, he alleges, Coleman was driving at high-speed and almost struck the cruiser. However, the investigative report disputes this.

A fellow officer said he was called to Morales' home after she called 911 saying Kovach was at her home, refusing to leave, and the Kovach told him he didn't believe Coleman to be a good person, having been arrested for marijuana possession.

Kovach was also called to a road rage incident during the situation, but did not appear to respond, according to the Chronicle-Telegram.