The many court filings related to the John Doe investigation into Governor Scott Walker’s campaigns for reelection have been leaked to the Guardian newspaper, who in a major story online today, presented those files for the first time to the public. The files shed light on the coordination between Gov. Scott Walker and conservative groups, including Wisconsin Club for Growth, and they raise questions about a link between the lead paint industry and a legislative effort that made it more difficult for people to sue paint makers.

The Guardian went through 1,500 pages of leaked documents that are being published in their entirety for the first time. The cache consists of a stack of evidence gathered by official prosecutors in Wisconsin who were conducting what was called a “John Doe investigation” into suspected campaign finance violations by Walker’s campaign and its network.

In July 2015, the Supreme Court of Wisconsin terminated the John Doe investigation before any charges were brought. The conservative majority of the court ruled that the prosecutors had made a basic misreading of campaign finance law and targeted individuals who were “wholly innocent of any wrongdoing.” Justices ordered many of the documents destroyed, but Guardian reporters said they obtained a surviving copy.

The leaked documents show $750,000 in donations to Wisconsin Club for Growth from Harold Simmons, the owner of NL Industries, one of the United States’ leading producers of lead used in paint until it was banned.

From the Guardian: “Republicans in the Wisconsin legislature made an initial attempt to change the law on the liability of lead paint producers shortly after Walker became governor. Act 2 was one of his opening gambits that he rammed through the legislature in less than a month after he came to office in January 2011. One of Act 2’s key provisions was to tighten tort law to make it much more difficult for lead victims to sue. Under its terms, anyone injured by lead paint who wanted to issue a new lawsuit had to prove that the company they were taking on was responsible for making the specific paint that was on their walls at the time they inhaled the toxin – a practically impossible task given the number of different manufacturers and the layer-upon-layer of paint on the walls of old houses.”

The measure in effect granted immunity to NL Industries and other lead producers from any new claims for compensation.

The Guardian article also noted that by the end of Scott Walker’s recall election, some $81 million overall was spent on the battle – equivalent to $23 for every registered voter in the state. The governor and other Republican groups and committees invested $58.7 million, while his Democratic rival and supporters were only able to muster less than half that amount, $21.9 million.

“The sheer increased volume of corporate money that has been brought into elections in recent years may go more on one side than the other,” explained Richard Briffault, a professor specializing in campaign finance law at Columbia law school, in the Guardian. “Corporations tend to lean more Republican.”