HELENA -- The Montana campaign coordinator for three conservative ballot measures has filed a lawsuit in federal court, attempting to blunt a state investigation of his financial backers.

The suit, filed last week by conservative activist Trevis Butcher of Winifred, says state Political Practices Commissioner Dennis Unsworth's investigation is violating free-speech rights of Butcher and his affiliated political groups.

Filed in U.S. District Court in Billings, the lawsuit sought to block Unsworth's requests that Butcher provide extensive information on Montanans in Action, a group that spent $1.1 million to promote three ballot measures.

In the meantime, Unsworth and Butcher's attorneys are continuing to negotiate over how much information Butcher must provide to cooperate with the investigation.

"It's my hope that the information we've requested from Mr. Butcher and the (affiliated) committees will be disclosed,'' Unsworth said Wednesday.

The investigation concerns the financial support for three ballot measures coordinated by Butcher: Constitutional initiatives 97 and 98 and Initiative 154.

CI-97 would have capped state spending; CI-98 made it easier to attempt to recall judges; I-154 allowed property owners to demand payment from the government if they felt government action had devalued their property.

All three measures had qualified for the Nov. 7 ballot, but were invalidated in October by a state judge, who ruled that "pervasive fraud'' occurred during the signature-gathering process that placed the measures on the ballot. They were essentially removed from the ballot.

Butcher is also treasurer for Montanans in Action, a new group that provided nearly all of the campaign funds for the ballot measures. Montanans in Action has not revealed its financial backers, and Butcher has said the law does not require their disclosure.

During the campaign, a rival group filed a complaint with the state Office of Political Practices, alleging that Montanans in Action is required to disclose its funding sources.

Unsworth, appointed as the new political practices commissioner in September, had said investigating the complaint is one of his top priorities.

The lawsuit filed by Butcher, Montanans in Action and the ballot-measure campaign groups said Unsworth, the state Democratic Party and others are using the investigation to harass and stymie Montanans in Action.

Subpoenas issued by Unsworth's office are violating free-speech and free-association rights because they will force the group to reveal its political associations and strategies, the suit said.

Unsworth said his office has been asking Butcher for information on Montanans in Action and related groups since July, and that nothing has been provided.

"We're simply trying to get some information so we can investigate a formal complaint,'' he said. "This investigation has to do with whether campaign contributions and expenditures were reported accurately, complete and in a timely way.''

Unsworth said he had hoped to shed some light on the funding before the election, but that he still has an obligation to continue the investigation and report the results to the public.