The National Archives is making the IRS further investigate why it can't recover a trove of Lois Lerner's emails.
The IRS told lawmakers that Lerner's computer crashed in mid-2011, leaving them unable to reproduce all of her emails for at least two years prior.
It has since said that Lerner's hard drive, which would have contained archived emails, was recycled in what was standard procedure for the agency.
Until last year, the IRS also recycled tapes storing back-up copies of emails after six months, raising serious questions about what information about Lerner's emails from 2009 to 2011 that investigators can learn.
The Archives oversee the Federal Records Act, which tries to ensure that agencies keep important documents safe. House Oversight Chairman Darrell Issa (R-Calif.) has questioned whether the IRS violated that law by not ensuring the safekeeping of Lerner's emails.
John Koskinen, the IRS commissioner, is expected to receive sharp questioning on that and other issues with Lerner's email before the House Ways and Means Committee.
Issa has supboenaed Koskinen to testify on Monday, and requested that Jennifer O'Connor, a former IRS lawyer now working in the White House counsel's office, testify Tuesday.