Former Internal Revenue Service official Lois Lerner speaks March 5 on Capitol Hill during the House Oversight and Government Reform Committee hearing on the the agency's targeting of Tea Party groups. Lauren Victoria Burke/AP hide caption

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House Ways and Means Committee Chairman Rep. Dave Camp, R-Mich. (center), flanked by the committee's ranking member, Sander Levin, D-Mich. (right), and Sam Johnson, R-Texas, listen on Capitol Hill April 9 as the panel debates whether IRS official Lois Lerner's refusal to testify to Congress deserves criminal prosecution. J. Scott Applewhite/AP hide caption

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Internal Revenue Service Director of Exempt Organizations Lois Lerner, as she was sworn in at a hearing Wednesday by the House Committee on Oversight and Government Reform. Chip Somodevilla/Getty Images hide caption

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Former IRS official Lois Lerner raises her hand as she's sworn in Wednesday at the start of a House Oversight & Government Reform Committee hearing. She declined to answer questions posed by Chairman Darrell Issa, invoking her Fifth Amendment right. Chip Somodevilla/Getty Images hide caption

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Lois Lerner, head of the IRS unit that decides whether to grant tax-exempt status to groups, leaves after being dismissed from a House Oversight and Government Reform Committee hearing on Wednesday. J. Scott Applewhite/AP hide caption

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Internal Revenue Service Director of Exempt Organizations Lois Lerner as she was sworn in at a hearing held Wednesday by the House Committee On Oversight & Government Reform. Chip Somodevilla/Getty Images hide caption

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