The documents, filed this week, offer some of the most definitive details yet on the probe. The investigation is being conducted as a so-called John Doe probe, a proceeding similar to a grand jury investigation where information is tightly controlled and witnesses can't speak publicly about their testimony.
The conservative group Club for Growth has filed a federal lawsuit seeking to stop the investigation, arguing prosecutors are harassing conservatives. Attorneys for a state Government Accountability Board investigator working on the probe filed a heavily redacted brief Wednesday asking U.S. District Judge Rudolph Randa to toss the lawsuit.
Wisconsin Reporter, a website funded by the conservative Franklin Center, was able to view the blacked-out portions by pasting them into a word processing program. The Associated Press replicated the process Friday.
The brief confirmed the five-county probe focuses on alleged illegal campaign coordination between conservative organizations and Republican candidates' campaigns during the 2011 and 2012 recalls. The elections were spurred by Democrats' outrage over Republican Gov. Scott Walker's law that stripped most public workers of nearly all their union rights. Democrats mounted a push to oust Walker himself, but the governor soundly defeated challenger Tom Barrett.
The investigation began in August 2012, the filing shows. The document notes that Judge Gregory Peterson, the state judge overseeing the probe, granted a request from Club for Growth members in January to quash five subpoenas and return materials obtained during the investigation.
It's still not known what was seized and it's unclear who received subpoenas beyond Club for Growth. The Wall Street Journal has reported the other targets were Walker's campaign, Wisconsin Manufacturers & Commerce and the conservative group Citizens for a Strong America.
The filing details the judge's rationale for his decision, quoting him as saying prosecutors mistakenly believe Wisconsin campaign finance law bans candidates from coordinating with outside groups on activities that don't specifically advocate for the candidate's election.
Still, about two weeks after issuing the order, Peterson put a hold on returning any seized material, saying a state appellate court should review his decision.
"The State's theory is that various parties engaged in illegal coordinated activities during the recent recall elections," Peterson said. "I concluded, however, that the coordinated activities are not prohibited under the statutes ... (but) the State's theory is not frivolous. In fact, it is an arguable interpretation of the statues."
The prosecutors have asked the 4th District Court of Appeals to review Peterson's decision. They explained their legal theories in filings in the federal case on Wednesday, saying any spending an outside group makes at a candidate's suggestion must reported as a campaign contribution, regardless of whether the money was used to expressly advocate for the candidate.
Two other lawsuits seeking to halt the investigation are still pending before the Wisconsin Supreme Court.