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Daniel Werfel, who headed the IRS after a controversy erupted over the agency's targeting of conservative groups, has quietly left government service.

The Washington Post, citing the White House Office of Management and Budget (OMB), reported that Werfel's last day with the government was December 31.

"I have not yet decided on what my next steps will be, but hope to do so in the near term," Werfel told the Post Monday. "My tenure with both OMB and the IRS left me energized for new challenges."

Werfel served as OMB controller from 2009 until last May, when he assumed the role of acting IRS administrator. His departure coincides with the confirmation of John Koskinen as IRS commissioner.

Under Werfel, the IRS launched an internal investigation after admitting to using improper techniques to determine the eligibility of conservative groups for tax-exempt status during the 2010 and 2012 elections. The review found no evidence of intentional wrongdoing by agency employees, nor did it find any proof that the targeting efforts were directed by the White House, conclusions questioned by some Republicans.

This past September, Lois Lerner, the career civil servant who headed the IRS division that handles applications for tax-exempt status, quietly retired after being placed on administrative leave in May.

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