House Republican investigators said Tuesday that the computer hard drive of ex-agency official Lois Lerner -- a key figure in the IRS targeting scandal -- was less damaged than the agency let on and that backup tapes containing her missing e-mails may still be available, Politico reported. The case of the former IRS official's lost emails became more complicated this week after a top agency official said he's no longer 100 percent sure there are no back-ups.

"If the IRS would just come clean and tell Congress and the American people what really happened, we could put an end to this," House Ways and Means Committee Chairman Dave Camp (R-Mich.) said in a statement on Tuesday. "Our investigators will not stop until we find the full truth."

In a quest to recover the missing emails, GOP-led Ways and Means Committee investigators learned Lerner's hard drive was damaged but recoverable by talking to IRS information-technology experts, after the government originally refused to make them available, according to the committee. GOP lawmakers are likely to raise the issues on Wednesday at a hearing with IRS Commissioner John Koskinen, who is scheduled to testify about issues related to the agency's targeting of tax-exempt groups based on their names and policy positions.

After discovering that Lerner's hard drive was only "scratched," House Republicans accused the IRS of ignoring in-house advice to seek outside help to retrieve information, Washington Post reported. "Where is the paper trail?" asked Barbara Rembiesa, the head of the International Association of Information Technology Asset Managers, a nonpartisan trade group of IT professionals. "There is a certification of destruction any time a piece of equipment is sent to a disposal company. ... Where is that?"

Additionally, House investigators are also attempting to determine whether the scratch was accidental or deliberate. "It is unbelievable that we cannot get a simple, straight answer from the IRS about this hard drive," Camp said.

Also on Tuesday, Republicans on the House oversight committee released testimony in which IRS Deputy Associate Chief Counsel Thomas Kane said the agency is no longer certain whether it recycled all of the backup tapes containing Lerner's e-mails. He said the question of whether some of the tapes still exist is "an issue that is being looked at."

Meanwhile, Lerner's admission in May 2013 that the agency inappropriately used search terms like "tea party," to review applications for tax breaks, which led to long delays, set off the furor last year. The former head of the tax-exempt unit in Washington has since stepped down and has been held in contempt of Congress by the House, according to Politico. "On June 13, more than one year into the investigation, and one month after the committee was promised it would receive all of Lerner's emails, Congress learned that potentially thousands of them, over roughly two years, were destroyed as a result of a 2011 computer crash," Fox News reported.

The hearing, which begins at 10 a.m. Wednesday, can be viewed live through the panel's video feed.