Federal Election Commission employees violated no rules in communicating with the Internal Revenue Service (IRS) about politically active nonprofit groups, according to a report from the FEC inspector general’s office.

As requested by congressional committees investigating the IRS’s targeting several years ago of conservative groups applying for tax-exemption, the FEC inspector general’s office conducted an extensive investigation into communications between FEC staff and the IRS regarding politically active nonprofits. According to Bloomberg BNA, the report was not made public but was presented this week to FEC commissioners and was referenced in the FEC inspector general’s annual report to Congress.

“No evidence was found that FEC staff attempted to improperly target any tax exempt organization” in coordination with the IRS, the report said.

For several years, the FEC has deadlocked on the issue of whether politically active nonprofits should register with the FEC as political committees and disclose their donors. Nonprofit donor disclosure has been an issue since the landmark 2010 Citizens United decision by the Supreme Court, which found that corporations, unions and other outside groups can spend unlimited amounts of money on political activities, as long as it is not in coordination with a party or candidate. Critics of the Citizens United decision claim it has led to the proliferation of “dark money” funneled into U.S. elections by political groups that do not have to publicly disclose their donors.