(J. Scott Applewhite/AP Photo)

House Republicans are angry after an email chain showed that former IRS chief Lois Lerner suggested that the agency should audit conservative Sen. Chuck Grassley.

Lerner, who has been the target of House hearings into the alleged targeting of conservatives, suggested the probe after she and Grassley were invited to speak at a seminar. The group mixed up their tickets and Grassley's invitation indicated that the group was also paying for Grassley's wife to travel and attend the seminar. Grassley's wife, Barbara, is a lobbyist.

"Looked like they were inappropriately offering to pay for his wife. Perhaps we should refer to Exam?" Lerner wrote in a Dec. 4, 2012 email to several individuals.

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Another IRS official, Matthew Giuliano, cautions Lerner against prematurely referring the case for further examination.

"Your and Grassley's invitations were placed in each other's envelopes," Giuliano replied. "Not sure we should send to exam. I think the offer to pay for Grassley's wife is income to Grassley, and not prohibited on its face."

Giuliano then suggested waiting for Grassley to accept and attend the speaking engagement, and subsequently determine whether the IRS should issue him a 1099. He also pointed out that Grassley would need to report the income on his 1040.

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An aide to Grassley noted that neither the senator nor his wife attended the event.

"This kind of thing fuels the deep concerns many people have about political targeting by the IRS and by officials at the highest levels," Grassley, R-Iowa, wrote in a statement this evening. "It's very troubling that a simple clerical mix-up could get a taxpayer immediately referred for an IRS exam without any due diligence from agency officials."

A waiver was signed by Grassley and his wife in order to make this information public, according to the committee.

"We have seen a lot of unbelievable things in this investigation, but the fact that Lois Lerner attempted to initiate an apparently baseless IRS examination against a sitting Republican United States Senator is shocking," Ways and Means Chairman Dave Camp wrote in a statement. "At every turn, Lerner was using the IRS as a tool for political purposes in defiance of taxpayer rights."

ABC News' Arlette Saenz contributed to this report