Congress broadened its investigation of the Internal Revenue Service's targeting of conservative groups and the disappearance of two years' worth of subpoenaed emails Friday by demanding that the White House and Treasury Department answer specific questions regarding the scandal.

The request, announced by Ways and Means Chairman Rep. Dave Camp, R-Mich., and Oversight Subcommittee Chairman Charles Boustany Jr., R-La., comes just weeks after the IRS claimed it could not retrieve thousands of subpoenaed emails belonging to Lois Lerner, the IRS official who retired in 2013 after admitting to the targeting scandal.

Federal officials have claimed in several congressional hearings that the email loss was an honest mistake. But Congress isn't convinced.

The White House and Treasury have both been asked by congressional investigators to answer the following questions:

— How they learned of Lerner’s hard drive crash and the resulting data loss;

— Who told them about these events; and

— Whether any employees discussed these matters, and the timing of their disclosure to Congress, with the IRS.

Congress also asked that the White House and Treasury provide details regarding all communications between five IRS officials whose emails were also mysteriously destroyed and federal employees in other departments, including the White House, Treasury, the Department of Justice, the Environmental Protection Agency, the Federal Election Commission and the Occupational Safety & Health Administration.

Lastly, Congress said the IRS must provide investigators with the following information:

— Names and background information of all IRS Information Technology employees involved in the attempts to retrieve information from custodial computers or storage devices;

— A timeline of these attempts;

— The makes, models, serial numbers, and locations of all failed devices;

— All documents related to the custodian computer failures and efforts to recover electronic data; and

— Other information relating to IRS email archival policy and whether it was followed in each of the custodian cases.

“We still can’t get straight answers from the IRS or this Administration about the circumstances of the destroyed IRS emails,” Camp and Boustany said in a joint statement. “And, we now know that the IRS, Treasury and White House knew that years’ worth of Lerner emails conveniently were destroyed, yet kept it secret from Congress. This Administration needs to live up to the transparency and openness it promised, and give this Committee all the documents it needs to complete its investigation,” the statement added.

In their Friday announcement, Camp and Boustany also provided a list of key dates in its ongoing investigation of the targeting scandal:

June 13, 2011 — Lerner hard drive crashes.

February 2014 — IRS discovers 2 years worth of Lerner documents are destroyed and unrecoverable.

April 2014 — White House and Treasury are informed of lost Lerner emails.

May 8, 2014 — IRS pledges to produce all Lois Lerner emails without limitation.

June 13, 2014 — Buried on page 15 of a letter from the IRS to Senate Finance Committee, the IRS informs Congress it has lost years’ worth of Lerner documents central to the investigation into the IRS targeting conservatives.

June 16, 2014 — Only under questioning by Ways and Means Committee investigators, the IRS admits that six other IRS employees pertinent to the investigation have experienced hard drive crashes.

June 20, 2014 — IRS Commissioner [John] Koskinen informs the committee that the Lerner hard drive has been destroyed and recycled, and cannot recall who informed the White House or Treasury of the destroyed hard drive.

Whether the White House and Treasury comply is anyone's guess (but we wouldn't put money on it).