CHARLESTON, S.C. -- A run-in between a skateboarder and a police officer left the skateboarder flat on his back.

And the whole thing was caught on tape.

SLIDESHOW: Cop Decks Skateboarder

Skateboarding is banned in downtown Charleston.

But that ban didn't stop Corey Dowds.

Earlier this month he was practicing some tricks in a city park. His brother Shane was videotaping the session.

Shane owns a skateboard shop and explained why boarders regularly defy the city ban.

"It's our job. It's what we do," he said.

"Why not just close up my business and go out of work."

The tape shows Corey hopping on his board onto a bench in a city park. Skateboarders call it grinding.

Suddenly an unidentifed police officer rushes into the frame and shoves Corey.

He goes head over heels and tumbles over a hedge, but pops right back up, surprised, but unharmed.

Shane offered an opinion of the controntation, "For a cop to assault a teenager is just insane."

"It should never happen," he added.

On the tape the officer begins shouting at both Corey and Shane.

The brothers have filed a complaint with the police department.

Officials there said the incident is under investigation.