In a knife fight of a congressional hearing , IRS Commissioner John Koskinen defended his agency , but he sparked an uproar from Republicans by admitting it destroyed a key hard drive wanted in an investigation , and he did not apologize for the data loss . `` I do n't think an apology is owed , not a single email has been lost since the start of this investigation , '' Koskinen told a dais full of skeptical GOP members on Friday . He argued the IRS has done its best to find the emails that originally went missing in 2011 . Those emails are central to an investigation of why the agency targeted tea party and other political groups for extra scrutiny when they applied for tax-exempt status . The hearing by the Republican-led House Ways and Means Committee focused on the week-old revelation from the IRS that a hard drive belonging to a former top agency official at the center of the congressional probe , Lois Lerner , crashed in 2011 . Tens of thousands of her emails saved on it dating to 2009 were destroyed . Lerner and that time frame are critical in the investigation . The targeting issue has its roots in the 2010 rise of the tea party and the Supreme Court Citizen 's United decision , which bolstered the ability of independent groups to engage in political activity . Lerner ran the division in charge of tax-exempt status and is the highest-ranking official directly connected to the targeting so far . She has since retired and refused to testify before Congress on the matter , citing her constitutional rights against having to do so . The House charged her with contempt of Congress for her refusal to speak . IRS pushes back . Koskinen told lawmakers on Friday that not only has the agency tried to retrieve the Lerner emails , but he also pushed back at Republican reports that emails of six other IRS employees , including a former chief of staff , are missing . `` It turns out ... that none of ( the chief of staff 's ) emails appear to be lost , '' Koskinen said , scolding the Republicans on the committee . `` Piecemealing out information about a possible problem simply results in press releases and angry letters to me . '' For their part , Republicans were blistering . They expressed frustration that has built up for the past week . `` The American people have no reason to trust the IRS ... on this issue , '' said Ways and Means Committee Chairman Dave Camp . The Michigan Republican pressed Koskinen on whether his agency knows exactly where the destroyed hard drive ended up . He replied that he was not sure if there was a serial number attached to the hard drive and that it was destroyed three years ago . Republicans drilled down on when the IRS knew about the hard drive problems . Time line key . The time line from Koskinen was nuanced . He said the agency knew in February that there was some kind of problem with Lerner 's hard drive , but that it took until late April or May to determine that the hard drive crash had erased data . Why did n't he tell Congress sooner ? Koskinen responded that the agency was trying to retrieve as many lost emails as possible first but decided to notify lawmakers after receiving a letter from the Senate Finance Committee last Friday . The committee indicated that it had completed its investigation and was doing a final check to make sure the IRS had sent every available Lerner email . Koskinen also pointed out that emails about the Lerner hard drive crash had been included in large bundles of documents , tens of thousands at a time , that the agency sent to congressional committees last fall . `` We 've provided the information , '' Koskinen began to say under questioning by Texas Republican Kevin Brady . `` You have not provided us the information ! '' Brady blasted back . `` At this point why should anyone believe you ? ... This is the most corrupt and deceitful IRS in the history ! '' Not to be believed . The outcry continued , leading to one of the most contentious exchanges of the day . `` This is unbelievable ! '' exclaimed a visibly irate Rep. Paul Ryan , a Wisconsin Republican . `` The apology should be to the American people . I do n't believe it . That 's your problem . No one believes you . '' Koskinen , whose tone was sharp and defensive at times , responded that he has had a long career in government . `` And that is the first time anybody has said they do not believe me , '' he said . `` I do n't believe you , '' Ryan repeated . `` That 's fine , '' Koskinen said . `` We can have a disagreement . '' Democrats defended the IRS as an agency overloaded with work and underfunded by Congress , and accused Republicans of turning the hearing into a political tribunal . `` Was ( Lerner 's ) hard drive crash a conspiracy ? No , '' said Rep. Sander Levin of Michigan , the top Democrat on the panel . `` The prevailing conspiracy in this matter is that of the Republican 's desire to stir their base , tie the problem to the White House and keep up this drumbeat until the November election . '' At one point Democratic Rep. Xavier Becerra of California gave the IRS leader friendly advice to take a deep breath before speaking . What 's up with the IRS emails ? Key questions about the controversy .
Sparks fly at congressional hearing on lost IRS hard drive . Washington (CNN) -- IRS destroyed hard drive , but did n't apologize . Republicans say agency is not to be believed , but Democrats say criticism is political .