An attorney for Hillary Clinton said he was "unable to obtain" emails from the former secretary of state's first months in office.
The admission came in a letter from David Kendall, Clinton's lawyer, to Patrick Kennedy, the agency's top records official.
Kennedy had asked Kendall to account for emails that were missing from the batch Clinton turned over to the State Department.
An agency spokesman admitted to the gap last month after Judicial Watch, a conservative nonprofit, uncovered records that indicated the State Department couldn't locate emails from the early days of Clinton's time as secretary.
Kendall said Clinton "does not have custody of emails sent or received in the first few weeks of her tenure, as she was transitioning to a new address, and we have been unable to obtain these."
According to Judicial Watch, the gap in Clinton's email collection stretches from Jan. to March 2009.