The official behind the IRS' conservative nonprofit targeting scandal, Lois Lerner, was friends with the Wisconsin regulator who targeted Wisconsin Gov. Scott Walker's conservative aides and allies.

Lerner and Kevin Kennedy, director of the Wisconsin Government Accountability Board, were friends for 20 years and traded emails on campaign finance, politics, and personal matters between 2011 and 2013, emails obtained by the Wall Street Journal reveal. That was the same time frame the IRS increased its harassment of conservative groups and Wisconsin prosecutors conducted a secret John Doe probe of Walker's allies, raising the troubling question of whether they coordinated their investigations.

After Walker's victory in a recall election, Lerner's long time friend Kennedy helped Milwaukee County prosecutors conduct an onerous, several-year investigation into Walker's political allies, complete with secret subpoenas for phone, text message and email records and armed, middle of the night raids on Walker associates' homes.

Under Kennedy, the Government Accountability Board hired four investigators to conduct the probe and set aside staff for the investigation, according to WSJ.

Ostensibly the purpose of the investigation was to determine whether Walker's campaign had illegally colluded with conservative groups, after Walker had busted state employee unions and Wisconsin Democrats lost the state election recall to Walker.

The investigation never uncovered any wrongdoing, and eventually federal Judge Rudolph Randa ordered it to end, ruling that the investigation had violated the First Amendment rights of Walker's associates. They were "pursuing criminal charges through a secret John Doe investigation against the plaintiffs for exercising issue advocacy [free] speech rights," Randa wrote.

The judge wrote that investigators also targeted Republican candidates for state Senate and that "all or nearly all right-of-center groups and individuals in Wisconsin who engaged in issue advocacy from 2010 to the present are targets of the investigation," a violation of the First Amendment.

The Wisconsin Club for Growth, one of the targets of the investigation, alleged that for months Kennedy had cooperated in the investigation after receiving the approval of six retired judges on his board, reported the Wisconsin State Journal. They also claim that even after the board voted to stop aiding the investigation, regulators and staffers continued to do so.

One of the groups involved with the pro-Walker "Verify the Recall" project was targeted with several IRS audits, according to True the Vote founder Catherine Engelbrecht. She said that her group was subjected to the audits after she filed for tax exempt status.

At the time of the investigation, Kennedy's Government Accountability Board even considered having Fox News host Sean Hannity and a local radio host, Charlie Sykes, subpoenaed, reported a Milwaukee Journal Sentinel columnist.

In the wake of the WSJ report, Wisconsin Republicans are calling for Kennedy's resignation.

"Friday's Wall Street Journal exposed a coordinated effort by the GAB's Kevin Kennedy and the disgraced Obama appointee at the IRS Lois Lerner," declared a joint statement from Republican state Sen. Alberta Darling and state Rep. John Nygren. "It is clear that the harassment of conservative groups by Lerner at the federal level directly coincided with the harassment of conservative groups right here in our state.

"We have completely lost confidence that the GAB can be trusted to operate in a non-partisan manner for the citizens of the state of Wisconsin with Kennedy in charge," they wrote. "In order for the GAB to return to its original mission, Kevin Kennedy must go."

Kennedy responded he wasn't going to "dignify" the Journal editorial with a comment, other than to say "it contains no facts showing that I or the Government Accountability Board did anything inappropriate or out of the ordinary," local Milwaukee stations reported.