A group of protesters rallied against American Tradition Partnership in Helena, Montana, on Wednesday, a day after the airing of Big Sky, Big Money, an investigation by FRONTLINE, ProPublica and Marketplace that uncovered potentially illegal collusion between the nonprofit group and political candidates.

ATP, in a statement on its website, said such claims were “false,” calling the film and related articles an “unsubstantiated, well-coordinated attack” on the group and its work.

Waving signs and chanting “ATP, go back to D.C.,” Wednesday’s protesters marched to the office of Jim Brown, ATP’s attorney, in the city of Helena, who greeted them with a tin of Halloween candy.

Later that evening, someone broke into the Montana Commissioner on Political Practices (COPP) office, according to a report in the local Independent Record. Nothing appeared to have been stolen.

The commissioner has been holding documents from Colorado that raised questions about whether ATP had been involved in inappropriate coordination with a number of political candidates. Those documents were “in a secure location and are not missing” after the burglary, the paper said.

Christian LeFer, the director of strategy for Western Tradition Partnership, which later changed its name to ATP, told ProPublica that the documents belonged to him and his wife, Allison LeFer, and that the papers had been stolen from her car in Denver. LeFer said in a statement that he and his wife have “scrupulously endeavored to avoid any possibility of illegal coordination.” Lefer and his wife have filed suit against COPP, asking the documents be returned.

Read the rest of our coverage and watch the full film here.

Sarah Childress, Former Series Senior Editor, FRONTLINE