WASHINGTON — The Treasury Department’s No. 2 official told Congress on Wednesday that his agency played no role in the Internal Revenue Service’s targeting of conservative groups.

Deputy Secretary Neal Wolin made the statement in testimony he prepared to deliver to the House Oversight and Government Reform Committee. At the same hearing, the star witness – IRS official Lois Lerner – was ready to invoke her constitutional right to not answer questions.

In his prepared remarks, Wolin said it was “absolutely unacceptable and inexcusable” that the IRS subjected tea party and other conservative groups seeking non-profit status to extra scrutiny from 2010 to 2012.

He said J. Russell George, the Treasury inspector general who focuses on taxes, told him last year that he was investigating IRS’s targeting of the groups.

“I told him that he should follow the facts wherever they lead. I told him that our job is to stay out of the way and let him do his work,” Wolin said.

“There is no indication that Treasury was involved in the inexcusable behavior at the IRS,” he added.

Lawmakers are trying to learn whether the IRS targeting was politically motivated. The inspector general and IRS officials have said there is no evidence of that.

As the hearing began, Oversight panel Chairman Darrell Issa, R-Calif., repeated a frequent complaint from lawmakers in the IRS episode — that IRS officials who knew earlier about the tartgeting didn’t tell Congress about it.

“Congress was misled. The American people were misled,” Issa said.

Lerner triggered the recent IRS uproar at a legal conference nearly two weeks ago, when she revealed that the agency’s targeting of conservative groups and apologized for the actions.

Lerner, 62, an attorney who joined the IRS in 2001, heads the unit that decides whether groups qualify for the status. She has come under fire from members of both parties, including Maryland Rep. Elijah Cummings, top Democrat on the Oversight Committee, who said in an interview Tuesday that she should lose her job.

George, the Treasury inspector general, has said he told Wolin in mid-2012 that he was investigating the IRS’ targeting of conservative groups, a report that was released last week. That means Wolin was the highest-ranking Treasury official to have known about the probe during last year’s elections, making him a focus of interest for lawmakers.

“What did you know and when? Who did you tell?” Rep. Jason Chaffetz, R-Utah, a senior member of the Oversight Committee, said Tuesday of what he hopes to learn from Wolin.

Lerner’s attorney, William W. Taylor III, has requested that she be excused from Wednesday’s hearing, writing in the letter that forcing her to appear “would have no purpose other than to embarrass or burden her.” But the committee has subpoenaed her and panel members say they expect her to attend.

“She better be there. We’re planning on it,” Chaffetz said.

In writing that Lerner would use her Fifth Amendment right to not incriminate herself, Taylor noted that the Justice Department has started an investigation into the IRS controversy. He also referred to a letter she received last week from Oversight Chairman Darrell Issa, R-Calif., saying she “provided false or misleading information on four separate occasions last year” to committee queries.

Staff of the Oversight Committee questioned Lerner and other IRS officials last year after receiving complaints from Ohio tea party groups that they were being mistreated by the IRS, said Meghan Snyder, spokesman for Rep. Jim Jordan, R-Ohio, a member of the committee.

In responses to the committee, Lerner didn’t mention that tea party groups had ever been targeted, according to documents. Her responses included 45-page letters in May 2012 to Issa and Jordan.

Lerner also met twice in early 2012 with staff from the House Ways and Means oversight subcommittee to discuss the issue, according to a timeline constructed by committee staff. The timeline said she didn’t mention at either meeting that conservative groups had been targeted.

Lerner’s revelation and apology at the May 10 legal conference came in response to a question that IRS officials later acknowledged they had planted with an audience member. Lerner’s disclosure came days before George, the inspector general, released his report detailing the IRS’ actions.

George’s report found that in June 2011, Lerner discovered that her unit was searching for organizations with words like “tea party” or “patriots” in their applications and subjecting them to tougher questions. She ordered the initial tea party criteria to be scrapped, but it later evolved to include groups that promoted the Constitution and the Bill of Rights, the report said. Lawmakers are curious about why the practice didn’t stop entirely.

A career civil servant who has run the division since late 2005, Lerner has not been disciplined for her role, IRS officials said. But with President Barack Obama demanding that IRS officials be held accountable for the problem, Acting Commissioner Steven Miller and another top agency official have announced their departures in recent days and many lawmakers believe more heads should roll.

George and Douglas Shulman, the former IRS commissioner who headed the agency while it was targeting conservative groups, are also scheduled to testify Wednesday.

On Tuesday, Shulman told the Senate Finance Committee that he learned in the spring of 2012 about his agency’s targeting of conservatives and George’s probe. He said he didn’t tell lawmakers or officials at Treasury — of which the IRS is part — because he only had sketchy information about the situation, was told it was being handled and believed it proper to let George’s office conduct its investigation.