MADISON - A man sued a GOP state lawmaker this week for taking his protest sign critical of Republicans — a move that could force the release of a video of the incident that so far has been kept from public view.

In May, Donald Johnson of Madison placed a sign in the Capitol that criticized Republican President Donald Trump — without naming him — as "corrupt" and "a serial groper." It said Republicans backed the president, "we the people be damned."

Johnson had a state permit to display the sign in the Capitol and taped a copy of it to the back of the sign.

That month, Rep. Dale Kooyenga (R-Brookfield) removed the sign and put it in his office. After Johnson complained about the missing sign, the Capitol Police saw on security video that Kooyenga had taken the sign.

He said he had removed it because he thought it was inappropriate. When the matter became public in July, Kooyenga initially told The Associated Press the sign said "damn all Republicans" and called multiple Republicans gropers, but the sign did not say those things.

On Thursday, Johnson sued Kooyenga in federal court in Madison for violating his First Amendment rights.

Kooyenga, who is now running for the state Senate, said Friday he did not realize there was a permit taped to the sign when he took it. He said he returned it as soon as he found that out and later publicly apologized.

"It was no intention to violate anybody's First Amendment rights," Kooyenga said.

Gov. Scott Walker's administration has refused to release the video of Kooyenga taking the sign in response to requests under the public records law from the Milwaukee Journal Sentinel and others.

Johnson's attorney, Lester Pines, said he would seek that video as part of the lawsuit because it is "extremely relevant evidence." He said he wanted Kooyenga to pay an unspecified penalty because he had taken the sign as a state official specifically because he didn't like what Johnson had had to say.

"He could have put up a sign next to it that said, 'Don't believe any of this.' That's how free speech works," Pines said.