A Republican political operative in Florida asked the alleged Russian hacker who broke into Democratic Party organizations’ servers at the height of the 2016 campaign to pass him stolen documents, according to a report Thursday by the Wall Street Journal.

In return, that operative received valuable Democratic voter-turnout analyses, which the newspaper found at least one GOP campaign consultant took advantage of the information. The hacker went on to flag that same data to Roger Stone, a longtime confidant of Donald Trump’s who briefly advised his presidential campaign, and who is currently under federal investigation for potential collusion with Russia.

The Wall Street Journal’s report presents the clearest allegations to date of collusion between people connected to Donald Trump’s campaign and Russia.

Cybersecurity experts were sounding the alarm as early as last July that Guccifer 2.0, which had tapped into both the Democratic National Committee and the Democratic National Campaign Committee, was connected to the Russian military intelligence apparatus. However, in September, Florida GOP consultant Aaron Nevins wrote to Guccifer 2.0 to tell the hacker to “feel free to send any Florida based information,” according to the Journal.

Guccifer 2.0 ended up passing Nevins 2.5 gigabytes of stolen documents, including information about Democrats’ get-out-the-vote strategy in Florida and other swing states, the Journal reported. Nevins then posted the documents on his blog, HelloFLA.com, under a pseudonym.

The stolen documents Nevins published on his blog and then passed along to Florida journalists included detailed analyses commissioned by the DCCC of specific Florida districts—reports that revealed how many dependable Democratic voters, likely Democratic voters, and frequent-but-not-committed voters resided in each area.

Stone told the Journal that while he did receive a link to Nevins’ blog from Guccifer 2.0, he didn’t share the stolen data published on the blog with anyone.

The Journal originally reported that one Florida Republican campaign consultant said he used the stolen information. The newspaper initially said a campaign consultant for U.S. Rep. Brian Mast (R-FL), Anthony Bustamante, ramped up his TV ad buys and dialed back a mailer effort. The Journal subsequently updated its story to reflect that a Mast spokesman said Bustamante stopped working for the campaign in June 2016, months before the stolen documents were published, and noted that it could no longer reach Bustamante.

This post has been updated.