A former IRS official at the center of the agency’s tea party controversy referred to some conservative Republicans as “crazies” and more in emails released Wednesday. A key GOP lawmaker said the remarks show that Lois Lerner was biased against conservative groups and illegally targeted them for extra scrutiny.

Lerner headed the IRS division that handles applications for tax-exempt status from nonprofit groups, including political organizations. In a series of emails with an associate in November 2012, Lerner made two disparaging remarks about some members of the GOP, including a profane characterization.

Rep. Dave Camp, who chairs the House Ways and Means Committee, released the emails Wednesday as part of his committee’s investigation. The Michigan Republican said the emails show Lerner’s “disgust with conservatives.”

In one email, Lerner called some conservatives crazies. In the other, she described them using an expletive.

Congress and the Justice Department are investigating whether the IRS improperly scrutinized applications for tax-exempt status from conservative groups during the 2010 and 2012 elections. Camp, in a letter to Attorney General Eric Holder, said the emails provide further proof that Lerner willfully targeted conservatives.

Lerner retired from the IRS last fall. Her lawyer could not be reached for comment.

Lerner has emerged as a central figure in several congressional investigations into the tax agency’s handling of applications for tax-exempt status by tea party and other conservative groups. She has twice refused to answer questions at congressional hearings and, in May, the House voted to hold her in contempt of Congress.

In June, the IRS told Congress that an untold number of Lerner’s emails were lost when her computer hard drive crashed in 2011. Despite that, it said it was able to provide congressional investigators with 67,000 emails to and from Lerner.

Lerner was apparently traveling in Great Britain in 2012 when she used her work email to send a series the messages containing the disparaging remarks to a personal associate who did not work at the IRS.

Lerner is the IRS official who first publicly disclosed in May 2013 that agents had improperly singled out tea party and other conservative groups for additional scrutiny when they applied for tax exempt-status. At the time, Lerner said a small group of agents working in a Cincinnati office was responsible.

A May 2013 report by the agency’s inspector general did not provide any proof of political bias on the part of agents. Since then, Republicans have been working to show conservatives were targeted as part of a conspiracy to stifle groups based on their political beliefs.