Werfel's email Thursday made no mention of Lerner. But a congressional aide who was briefed on the matter said Lerner was placed on administrative leave. The aide spoke on condition of anonymity because a personnel matter was involved.
Lerner is the IRS official who first publicly disclosed on May 10 that IRS agents had been targeting tea party and other conservative groups for additional scrutiny when they applied for tax-exempt status. At the time she apologized on behalf of the IRS, but it wasn't enough to stop a firestorm of criticism from the White House and Congress.
Lerner also provided one of the most electric moments since the controversy erupted when she unwaveringly but briefly defended herself before the House Oversight and Government Reform Committee on Wednesday.
"I have not done anything wrong," she told the committee, reading from a written statement. "I have not broken any laws, I have not violated any IRS rules or regulations, and I have not provided false information to this or any other congressional committee."
Then, she refused to answer lawmakers' questions, invoking her constitutional right against self-incrimination. A few minutes later, she was excused. As she boarded an elevator, several of the men who escorted her briefly jostled with TV camera operators who were trying to film her.
Lerner learned in June 2011 that agents were singling out groups with "Tea Party" and "Patriots" in their applications for tax-exempt status, according to a report by the agency's inspector general. Lerner ordered agents to scrap the criteria immediately, but later they evolved to include groups that promoted the Constitution and the Bill of Rights.
It finally stopped in May 2012, when top agency officials say they found out and ordered agents to adopt appropriate criteria for determining whether tax-exempt groups were overly political.
Former IRS Commissioner Douglas Shulman told two congressional committees this week that he first learned in the spring of 2012 that conservative groups had been improperly singled out for additional scrutiny. However, after learning that the practice had stopped and that the inspector general was investigating, Shulman said he didn't tell anyone in the Treasury Department or the White House about it. The IRS is part of the Treasury Department.
Shulman, who was appointed by President George W. Bush, left office in November, when his five-year term expired.
On Thursday, the two leaders of the Senate Investigations subcommittee accused Lerner of misleading committee staff just a few days before it she made the controversy public.
Subcommittee Chairman Carl Levin, D-Mich., and the top Republican member, Arizona Sen. John McCain, called on the IRS to immediately suspend Lois Lerner from her job as director of the IRS division that handles applications for tax-exempt status.
On April 30, committee staff interviewed Lerner and seven of her colleagues for six hours, the senators said in a letter to Werfel.
"That interview covered, among other topics, how the IRS determines which groups to review, what actions are taken in connection with the IRS reviews, and how the laws and regulations are used to examine those groups," the senators wrote. "Ms. Lerner failed to disclose the internal controversy."
Lerner, 62, is an attorney who joined the IRS in 2001. In her brief appearance Wednesday, she expressed pride in her 34-year career in federal government, which has included work at the Justice Department and Federal Election Commission. AT the IRS, she oversaw 900 workers and a budget approaching $100 million.
Corbin, the new acting director, began his IRS career in Atlanta in 1986, Werfel said.
"Ken is a proven leader during challenging times. He has strong management experience inside the IRS handling a wide range of processing issues and compliance topics as well as taxpayer service areas," Werfel said. "Combined with his track record of leading large work groups, these skills make him an ideal choice to help lead the Exempt Organizations area through this difficult period."