The Internal Revenue Service is missing e-mails from five more employees whose records could shed light on the agency’s targeting scandal, but there are no signs that its personnel have intentionally destroyed evidence, according to an IRS review.

In a report to four congressional committees on Friday, the IRS said hard-drive crashes are to blame for the lost communications and that the computer malfunctions “appear to be the same sorts of issues routinely experienced within the IRS, in other government agencies and in the private sector.”

The report also noted that the crashes occurred before the start of investigations into how the agency identified nonprofit advocacy groups for extra scrutiny. The IRS’s inspector general released an audit last year that said the agency inappropriately targeted certain organizations based on their names and policy positions.

The IRS notified Congress earlier this year that it is missing years worth of e-mails from Lois Lerner, the ex-agency official whose department was at the center of the targeting scandal. Lerner retired from the government in September 2013, about four months after acknowledging her office’s mistakes. She has invoked her Fifth Amendment right against testifying at two congressional hearings on the targeting matter.

IRS chief John Koskinen testified at a hearing in June that the agency lost many of Lerner’s e-mail records after her hard-drive crashed in 2011. He said the agency tried unsuccessfully to recover the data and then sent the broken device away for destruction.

The IRS said in its report on Friday that the agency now knows of five more employees who are missing e-mails because of hard-drive crashes. The staff members include: Judy Kindell, who was Lerner’s former senior adviser; IRS tax-law specialist Justin Lowe, who worked with Kindell; IRS manager Ron Shoemaker, who helped oversee the cases in question; and two Cincinnati-based IRS employees who had worked on some of the cases.

The agency said all of the employees contacted IT staff and attempted to recover their data after their computers malfunctioned.

The IRS said in a recent court filing that it also “removed or wiped clean” information from Lerner’s Blackberry in June 2012, after congressional staffers began questioning her — and in the same month that TIGTA began its review of the matter. The mobile device may have contained duplicates of Lerner’s missing e-mails.

The IRS has not explained why it erased information from Lerner’s Blackberry in June 2012.

Republicans have suggested that the Obama administration used the IRS to hinder conservative and tea party groups during the past two election cycles, when the agency used the inappropriate screening methods. Democrats have rejected that theory, noting that the IRS pulled aside a handful of left-leaning groups for extra scrutiny as well.

The Senate Permanent Subcommittee on Investigations issued a report last week saying it found “no evidence of IRS political bias” in the IRS’s targeting actions. It also criticized the inspector general’s audit, saying the review failed to make clear that the screening methods affected left-leaning organizations.

Republicans on the panel issued a dissent in the Senate report, saying the TIGTA audit was “accurate and proper” and that 83 percent of the groups that the IRS pulled aside for extra scrutiny were right-leaning.

The IRS sent the results of its internal review to the House Oversight and Government Reform Committee; the House Ways and Means Committee; the Senate Finance Committee; and the Senate Permanent Subcommittee on Investigations.