WASHINGTON (AP) -- Defiant before skeptical Republicans, the head of the IRS refused to apologize Friday for lost emails that might shed light on the tax agency's targeting of tea party and other groups before the 2010 and 2012 elections.
Instead, Commissioner John Koskinen accused the chairman of a powerful House committee of misleading the public by making false statements based on incomplete information.
The contentious back-and-forth didn't end there. Later in the hearing, Rep. Paul Ryan, the Republicans' vice presidential candidate two years ago, told Koskinen bluntly that "nobody believes you."
"I have a long career. That's the first time anybody has said they do not believe me," said Koskinen, who came out of retirement in December to take over the IRS. Previously, he served in other positions under Presidents Bill Clinton and George W. Bush.
The hearing showed that emotions are running hotter than ever in the dispute over the IRS and political fundraising.
Rep. Dave Camp of Michigan, chairman of the Ways and Means Committee, asked Koskinen to testify a week after the IRS disclosed that it had lost an untold number of emails to and from Lois Lerner. Lerner headed the division that processes applications for tax-exempt status during a time when, the IRS has acknowledged, agents improperly scrutinized applications from tea party and other conservative groups.
Camp was clearly expecting Koskinen to be more contrite.
"What I didn't hear in that was an apology to this committee," Camp said after Koskinen's opening statement.
"I don't think an apology is owed," replied Koskinen.
The IRS commissioner also dismissed Camp's call for a special prosecutor to investigate, saying it would be "a monumental waste of taxpayer funds."
Later, White House spokesman Josh Earnest was equally dismissive. "I'm not sure that there's a whole lot more to be discovered here," Earnest said.
The IRS says it lost Lerner's emails when her computer crashed in June 2011. At the time, technicians went to extraordinary means to recover them, even sending Lerner's hard drive to agency's forensic lab, Koskinen said. But to no avail.
In 2011, the IRS had a policy of backing up emails on computer tapes, but the tapes were recycled every six months, Koskinen said. He said Lerner's hard drive was recycled and presumably destroyed.
"I am sitting here listening to this testimony. I just, I don't believe it," said Ryan. "That's your problem. Nobody believes you."
When Koskinen objected, Ryan cut him off: "I don't believe you."
Democrats on the committee were much more accommodating to Koskinen.
"I want to apologize to you for the way you're being treated this morning," said Rep. John Lewis, D-Ga. "I thought this was a hearing and not a trial."
The IRS was able to generate 24,000 Lerner emails from the 2009 to 2011 period because she had copied in other IRS employees. Overall, the IRS said it is producing a total of 67,000 emails to and from Lerner, covering the period from 2009 to 2013
On Monday, IRS technicians told the congressional panel's staff that the hard drives of six other workers involved in the probe had also crashed. Among them was Nikole Flax, who was chief of staff to Lerner's boss, then-deputy commissioner Steven Miller.
On Friday, Koskinen increased the total to eight - including Lerner's - saying the agency had discovered another crashed hard drive.
Committee Republicans likened the revelations to the drip, drip, drip of a scandal.
However, Koskinen rejected statements made by Camp earlier his week that the crashes had destroyed records kept by Flax. Koskinen said Flax's emails were retrieved from a second computer. He said it is still not known whether emails have been lost because of the other crashes.
Koskinen suggested that he would no longer provide incremental reports on the crashed hard drives to Camp, for fear it would be distorted in the media.
"So those press releases with regard to Nikole Flax were inaccurate and misleading, and it demonstrates why we will provide this committee a full report about the (hard drives) when it is completed," Koskinen said. "We're not going to dribble out the information and have it played out in the press."
After the hearing, Camp said he still has questions about Flax's computer.
"We don't know where her hard drive is, we don't know that the hard drive to the laptop has been saved," Camp said. "He said he hasn't secured it. I think he has a lot of questions to answer about Nikole Flax before he throws any accusations in my direction."
A little more than a year ago, Lerner disclosed that IRS agents had improperly scrutinized applications by tea party and other conservative groups from 2010 to 2012.
At the time, she apologized on behalf of the agency. Since then, she has refused to answer questions at two congressional hearings and has been forced to retire under threat of being fired. Earlier this year, the House voted to hold her in contempt of Congress.
The Justice Department and three congressional committees, including Ways and Means, are investigating the IRS.
Congressional investigators have shown that IRS officials in Washington were closely involved in handling tea party applications, many of which languished for more than a year without action. But so far, they have not publicly produced evidence that anyone outside the agency directed the targeting or knew about it.
If anyone outside the agency was involved, investigators were hoping for clues in Lerner's emails. The White House said Wednesday it has found no emails between anyone in the executive office of the president and Lerner.