Denver police Sgt. Michael Karasek may have gone a little overboard in an incident involving a motorist and an anti-Bush bumper sticker. So far overboard, he’s under investigation.

A Denver police sergeant is under investigation for allegedly threatening to arrest a woman Monday for displaying on her truck a derogatory bumper sticker about President Bush.

“He told her that this was a warning and that the next time he saw her truck, she was going to be arrested if she didn’t remove the sticker,” said Alinna Figueroa, 25, assistant manager of The UPS Store where the confrontation took place. “I couldn’t believe it.”

Sergeant Karasek allegedly told the motorist that it is illegal to display a bumper sticker with a profane message. Her’s said, “F–k Bush.” In addition to threatening to arrest her if he ever saw her truck again with the bumper sticker on it, he also allegedly told her never to return to the area.

Sounds like Sgt. Karasek could use a lesson in the First Amendment…and the Fourth. Maybe anger management classes as well.