The chief technology officer at the IRS was "blown away" after learning backup tapes that likely contained messages to and from controversial ex-official Lois Lerner were destroyed, according to an internal government watchdog report. 

The 1,600-page report, prepared by the Treasury Inspector General for Tax Administration, examined the agency's handling of Lerner's missing emails and apparent computer crash. Lerner is the former official at the heart of the scandal over IRS targeting of Tea Party and other conservative groups, but lawmakers were told last year that some of her electronic communications had been lost. 

The effort to recover those files has seemingly been marked by a string of blunders. Inspector General J. Russell George first told lawmakers last week that 422 backup tapes were "magnetically erased" around March 4, 2014, meaning thousands of emails might never be recovered. 

The IG report, which is not expected to be made public but has been viewed by Fox News, does not point to any deliberate cover-up. The report says investigators found "no evidence that the IRS and its employees purposely erased the tapes in order to conceal" some of the emails in question. 

However, the report demonstrates the IRS did a sloppy job retaining documents despite a House Ways and Means Committee directive to do so. 

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Late Thursday Rep. Elijah Cummings, D-Md., ranking member of the House Committee on Oversight and Government Reform, responded to the report, saying, “After spending more than $20 million and three years investigating, the Inspector General’s conclusions remain the same:  there is no evidence to substantiate Republican claims of political motivation, White House involvement, or intentional destruction of evidence.  It’s time to stop this political witch hunt and focus on investigations that impact American’s lives."

According to the report, IRS Chief Technology Officer Terry Milholland told the IG office he was "blown away" after learning the tapes had been demagnetized -- a process known as "degaussing." This was done at the IRS's IT center in Martinsburg, W.Va. Those tapes are believed to have contained Lerner emails that "were responsive to Congressional demands and subpoenas," the report says. 

"Backup tapes were destroyed as a result of IRS management," the report says, noting officials failed to appropriately follow a May 2013 directive from Milholland concerning record preservation. 

The report further states that the IRS "did not fully identify as a source or perform recovery attempts for email" associated with Lerner. It says that as many as "23,000 to 24,000 email messages may not have been provided to Congress." 

Beginning in the summer of 2011, according to the report, there was an effort by the IRS to recover the failed hard drive belonging to Lerner. 

A July 19, 2011, email from Carl Froehlich, who headed the service's "Agency Wide Shared Services" division, to Lerner declared that "Lillie Wilburn" was on the case. Wilburn is the IRS's program manager of network services for IT in Atlanta. 

"It may be too late - don't send them off to the hard drive cemetery," Lerner wrote to the IRS' IT department on July 20. 

On Aug. 5, 2011, Wilburn wrote to Lerner: "Unfortunately the news is not good. The sectors of the hard drive were bad which made your data [unrecoverable]. I am very sorry. Everyone tried their best." 

Lerner then replied: "Thanks for trying. It really do appreciate the effort. Sometimes stuff just happens." 

Before leaving the agency, Lerner led the division that came under fire for allegedly singling out conservative groups for additional scrutiny as they sought nonprofit status.