Federal investigators have begun an investigation into the source of a audio recording of private strategy sessions earlier this year featuring Senate GOP Leader Mitch McConnell's re-election team plotting against a potential opponent, actress Ashley Judd.

McConnell campaign manager Jesse Benton said Tuesday that the campaign is working with the Federal Bureau of Investigation and the U.S. Attorney's office in Louisville to uncover who recorded a Feb. 2 meeting in Kentucky – attended by McConnell himself -- which was published earlier today by the liberal magazine Mother Jones.

Alex Wong / Getty Images

Senate Minority Leader Sen. Mitch McConnell (R-KY)

McConnell's campaign has vehemently denied that anyone from its staff was responsible for the leak, and has begun to pursue a criminal investigation into the matter.

"Senator McConnell’s campaign is working with the FBI and has notified the local U.S. Attorney in Louisville, per FBI request, about these recordings," said McConnell campaign manager Jesse Benton. "Obviously a recording device of some kind was placed in Sen. McConnell’s campaign office without consent. By whom and how that was accomplished will presumably be the subject of a criminal investigation."

In the tapes, McConnell and a handful of aides are heard discussing opposition research against would-be Democratic challengers next fall, most prominently Judd. While Judd eventually declined to challenge McConnell for re-election in 2014, the aides were heard on-tape discussing research into Judd's background, including her mental health history and religion.

The FBI confirmed that is has begun an inquiry into the recording through a spokeswoman on Tuesday.

"We are looking into the matter," Mary Trotman, a spokeswoman for the FBI office in Louisville, told NBC News. She said FBI agents have already listened to the recording -- and are "following all the logical steps" to determine if it was made in violation of federal law.

Already, the McConnell campaign -- which has been early and aggressive in organizing the top Senate Republican's re-election effort -- has suggested that the recordings were part of a Democratic smear, although it has not provided any evidence to substantiate that allegation.

"We’ve always said the Left would stop at nothing to attack Sen. McConnell, but Watergate-style tactics to bug campaign headquarters are above and beyond," said Benton.

Speaking Tuesday afternoon on Capitol Hill, McConnell insinuated that a liberal group in his home state -- ProgressKY, which launched an incendiary attack on McConnell's wife's ethnicity -- was to blame for a bugging.

"As you know, last month my wife's ethnicity was attacked by a left-wing group in Kentucky," McConnell said. "And then, apparently, they bugged my headquarters. So I think that pretty well sums up the way political left is operating in Kentucky." (A spokesman for McConnell later denied the senator was referring to ProgressKY specifically, but rather, speaking more generally.)

A spokesperson for Judd fired back at McConnell, asserting his research into her mental health history served as a reason to defeat him.

"This is yet another example of the politics of personal destruction that embody Mitch McConnell and are pervasive in Washington DC," said the spokesperson. "We expected nothing less from Mitch McConnell and his camp than to take a personal struggle such as depression, which many Americans cope with on a daily basis, and turn it into a laughing matter. Every day it becomes clearer how much we need change in Washington from this kind of rhetoric and actions.”

In a phone interview with NBC News, Mother Jones' David Corn says he and his publication have "no comment" about any FBI investigation into how he obtained the recording of the McConnell campaign's strategy session on actress Ashley Judd. 

"This story speaks for itself," Corn said.

The magazine itself added in a statement:

We are still waiting for Sen. Mitch McConnell to comment on the substance of the story. Before posting this article, we contacted his Senate office and his campaign office—in particular, his campaign manager, Jesse Benton—and no one responded. As the story makes clear, we were recently provided the tape by a source who wished to remain anonymous. We were not involved in the making of the tape, but we published a story on the tape due to its obvious newsworthiness. It is our understanding that the tape was not the product of a Watergate-style bugging operation. We cannot comment beyond that.

While McConnell has won four additional terms since winning his first in 1984, the Kentucky Republican has been aggressively targeted for defeat by Democrats, who argue McConnell is not especially popular in his state, and is to blame for much of the procedural gridlock in the Senate.

NBC's Mark Murray, Domenico Montanaro and Michael Isikoff contributed reporting.

This story was originally published on Tue Apr 9, 2013 10:44 AM EDT

AP

President Barack Obama (left) campaigning for former New Jersey Gov. Jon Corzine (right) in Holmdel, N.J., July 16, 2009. Corzine lost reelection to Republican Chris Christie.

Jon Corzine, now the center of an FBI investigation into the handling of hundreds of millions of dollars invested in his securities firm, was one of the leading Wall Street fundraisers for President Obama’s campaign and suggested to investors that he might take a top administration post if the president were re-elected.

His new legal troubles, sparked by the bankruptcy filing of his investment firm, MF Global, could complicate the president’s efforts to raise money from the financial community given Corzine’s central role in those efforts.

A recent list of top “bundlers” or elite fundraisers released by Obama’s campaign listed Corzine in the highest category -- reporting that he had raised more than $500,000 for the campaign. A substantial chunk of those funds were collected at a $35,800 per ticket fundraiser that Corzine hosted at his wife’s spacious Fifth Avenue apartment last April -- an event that was touted at the time as part of a concerted effort by the president’s campaign team to reach out to well-heeled Wall Street donors who had been alienated by some of his policies and previous public comments.  

Just a few months after that event, Corzine’s firm, MF Global, surprised many Wall Street investors by issuing highly unusual securities notes that appeared to highlight Corzine’s close relationship with the White House: The notes suggested that the former New Jersey governor might be in line for a top administration post should the president get re-elected.

The notes promised to pay an extra 1% in interest rates in the event of “the departure of Mr. Corzine as our full time chief executive officer due to his appointment to a federal position by the President of the United States and his confirmation…by the United States Senate prior to July 1, 2013.”

Some veteran Wall Street analysts said they couldn’t recall ever seeing such a contingency written into securities notes. “It was bizarre,” said Christopher Whalen, a Wall Street analyst.

There was speculation in the financial press at the time that Corzine might be a candidate to replace Tim Geithner as Secretary of the Treasury. But today, an Obama campaign official declined to comment on Corzine’s legal troubles -- or whether Corzine was ever being considered for an appointment.

“He’s one of our volunteer fundraisers,” said the campaign official when asked about Corzine, adding that the president’s is the only presidential campaign that discloses the identities of its bundlers.

The investigation into Corzine’s firm, MF Global, was triggered by reports of hundreds of millions of dollars in missing funds and findings by regulators that MF Global may have broken rules requiring it to keep client’s money and company funds in separate accounts.

Ironically, on the same day that Corzine’s legal troubles were erupting -- posing potential problems for the president’s Wall Street fundraising efforts -- GOP rival Mitt Romney was holding one of his biggest New York fundraisers yet at a midtown Manhattan hotel.

A copy of the invite shows the fundraiser had more than 100 co-chairs, many of them top executives on Wall Street such as hedge-fund billionaire John Paulson, who has already donated $1 million to a “Super PAC” backing Romney’s candidacy.