Who Alerted Treasury Dept. of Missing IRS Emails Months Before Congress?

We now have the answer to one question in the IRS missing email investigation: who at the IRS notified Obama administration officials that emails were missing...while Congress, which subpoenaed the documents, was left in the dark. Here's my latest report for Sinclair Media television affiliates:

[ilink url="http://www.wjla.com/articles/2014/09/irs-says-it-has-lost-emails-from-5-more-employees-106820.html"]Who at the IRS clued in fellow Obama officials about missing subpoenaed emails prior to notifying Congress?[/ilink]