IRS Commissioner John Koskinen said it may be possible to recover emails thought to be lost for good.
Those emails are part of an ongoing investigation into the agency's targeting of Tea Party and other conservative groups.
Koskinen confirmed the existence of "back-up tapes" for Lois Lerner's computer hard drive at a hearing Wednesday on Capitol Hill.
Investigators are reviewing the tapes to see if any information can be recovered and shed light on thousands of Lerner's missing emails.
The former official was in charge of the IRS tax-exempt division at the center of the controversy.
Her hard drive was destroyed in 2011 after a computer crash, but House investigators believe the hard drive was just "scratched" and most of its contents could have been restored.
Republicans accuse the agency of stonewalling and a possible cover up, a charge Koskenin denies.
"The testimony I've given in the past was accurate as of the time with what I knew. I testified as to what I knew. Right now the question is do I know anything more about tapes, backup tapes? And the answer is I don't know any more other than the IG [inspector general] is investigating whether there are back-up tapes and whether they're, in fact, recoverable," he told the committee.
Republicans plan to hold another hearing into the targeting scandal next week.