A grand jury subpoenaed emails and financial statements in July from Jesse Benton, who resigned Friday from Sen. Mitch McConnell's re-election campaign, according to a report published by OpenSecrets.org.

The grand jury is one of two, according to OpenSecrets, looking into improper payments made by Ron Paul's 2012 presidential campaign to an Iowa state lawmaker in exchange for the lawmaker's endorsement in the Iowa caucuses. Benton, who was Paul's campaign manager, has not been charged with a crime.

Benton resigned Friday, after the now-former state lawmaker pleaded guilty to having received $73,000 from Paul's campaign, although Benton said any suggestions that he was involved in the scheme were "unsubstantiated."

"I hope those who know me recognize that I strive to be a man of integrity," Benton said in a statement Friday.

But Benton's subpoena one month prior to his resignation adds another wrinkle, raising questions about what McConnell's campaign might have known about the deepening scandal and Benton's role in it.

In an interview Thursday with the Lexington Herald-Leader, McConnell's new campaign manager Josh Holmes said Benton had not mentioned the subpoena.

"From his first day at Team Mitch to his last, there were never any allegations brought against Jesse of any wrongdoing with his previous campaign work," Holmes told the Herald-Leader.

Benton also led Rand Paul's successful 2010 campaign for Senate, and was thought to be a shoo-in to help run Paul's bid for president.

Neither Benton nor McConnell's campaign responded to requests for comment.