The Internal Revenue Service has said it isn't going to apologize for a loss of emails that were part of an ongoing investigation. The revelation has left many questioning the transparency and integrity of the tax agency as the probe by American lawmakers continues.

It also may support what some of the general public thinks, that the IRS believes it is above oversight by even democratically elected officials.

IRS Commissioner John Koskinen has said the agency is not going to be apologizing for the loss of emails after a hard drive crashed in 2011, making a number of emails inaccessible for the probe, arguing that IRS' emails have not been lost since.

"I don't think an apology is owed," Koskinen said during a tense hearing with lawmakers on Capitol Hill. "Not a single email has been lost since the start of this investigation."

Koskinen did say the IRS is moving toward restoring those emails and argued the losses of messages occurred before the investigation began.

But Republicans, who are leading the investigation into the IRS, are claiming that the agency is attempting to "cover-up" IRS treatment of political organizations, which have come under scrutiny by the IRS in recent months. They are accusing the IRS of dealing with the Tea Party in an improper manner over its tax-exempt status development.

"The American people have no reason to trust the IRS or, frankly, the administration on this issue," said House Ways and Means Chairman Dave Camp, R-Mich.

Rep. Paul Ryan, R-Wis., has gone even further, saying he didn't trust Koskinen's testimony.

"This is not being forthcoming, this is being misleading again," he said. "This is a pattern of abuse, a pattern of behavior that is not giving us any confidence that this agency is being impartial. I don't believe you. This isn't credible."

But Democrats are arguing the Republicans are pushing too far, saying they are conducting a "witch hunt" against the IRS over its ability to track political organizations and their dealings with donations and money.

The case, and the ongoing debate over the IRS actions, has sparked a nationwide debate over taxes, tax fraud and the use of money in the political sphere. The IRS has allegedly been on the prowl, going after political groups and their funding, which has many organizations, especially Republicans, frustrated over how they feel they are being targeted by the IRS over their funding.