The House Oversight committee’s top Democrat on Friday will release new evidence that the Internal Revenue Service targeted both progressive and conservative groups for extra scrutiny during the 2010 and 2012 election cycles.

Rep. Elijah Cummings (D-Md.) said in a draft letter to committee chairman Darrell Issa (R-Calif) that congressional investigators have discovered training materials from an July 2010 “Screening Workshop” that prove IRS agents were told to be on the lookout for groups from both sides of the political spectrum.

A PowerPoint presentation from the workshop told IRS processors to screen for names that look like “tea party,” “patriots,” ” 9/12 Project,” and “progressive.” It noted that such groups “may be more than 50% political,” which could disqualify them from tax-exempt status.

Minutes from the training session show that the IRS also instructed agents who had any doubts about groups to “err on the side of caution and transfer to 7822,” an IRS office in Cincinnati that reviewed applications for tax-exemption.

An audit by IRS inspector general J. Russell George found that the agency inappropriately targeted groups based on ideology rather than looking for politically neutral signs of campaign activity.

Republicans seized on the findings to suggest that the Obama administration had systematically bullied its critics during critical elections. The issue led to public outrage, agency apologies, congressional hearings, a Justice Department probe and an IRS shakeup that included the resignation of acting commissioner Steven Miller under pressure from the White House.

George testified before Congress in May that his office was unable to determine whether any cases in the audit involved progressive groups. He said the names “in many instances were neutral, in that you couldn’t necessarily attribute it to one particular affiliation or another.”

Cummings said in his letter that the new IRS documents “raise serious questions about the inspector general’s report, his testimony before Congress, and his subsequent assertions in letters to members of Congress.” He also asked Issa to recall George for further testimony at a hearing the chairman scheduled for July 18.

Earlier this month, House Democrats released IRS documents showing that terms such as “progressive,” “health care legislation” and “medical marijuana” appeared on a multipart “Be on the Lookout” list, or BOLO, that helped agents determine which groups deserved additional screening.

Despite that revelation, the BOLO could still be problematic for the IRS. A category on the list called “emerging issues” included only conservative search terms at the outset.

Terms such as “progressive” and “medical marijuana” appeared in separate parts of the BOLO that included diverse search criteria. Questions remain about when and how those terms were used by IRS screeners, as well as whether those categories were even relevant to the audit. Both the IRS and George’s office have said they’re looking into those matters.

Cummings’ letter said the IRS added the phrase “‘Occupy’ Organizations” to the BOLO in January 2012, including that search criteria under the “watch list” category.

Republicans have downplayed the recent revelations about search criteria associated with left-leaning groups.

“Our Democratic colleagues should stop trying to derail the investigation by defending IRS officials with distorted claims equating the systematic scrutiny of Tea Party groups with the more routine screening progressive groups received,” Issa said in a statement last week.

In an e-mail on Friday, Issa spokesman Frederick Hill pointed out that the meeting minutes refer to a “Tea Party coordinator” that the agency assigned to review some of the screened applications.

“That line presents further evidence that Tea Party groups were differentiated and segregated from other applications and is consistent with other evidence that Tea Party groups were treated differently,” Hill said. “The fact that there is no indication (on the document or elsewhere) that there was a “Progressives coordinator” is further evidence of disparate treatment.”

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