Text messages between several top officials in the Department of Defense and the Army were deleted shortly after they left the Trump administration, leaving a significant hole in correspondence that could have happened on the day of the Capitol attack.

The former acting Secretary of Defense, Christopher Miller, and the former Army Secretary, Ryan McCarthy, were among the senior members of the Trump administration that American Oversight wanted to speak to.

Six days after the riot at the Capitol, a Freedom of Information Act lawsuit was filed.

The watchdog group wrote in a press release that the lawsuit seeks the release of communications those officials had with former President Trump and others.

The Defense Department and the Army told former employees of their agencies that their phones couldn't be reproduced because they were wiped after they left.

When an employee leaves the Department of Defense or the Army he or she will lose his or her phone, according to the court document. The text messages were not preserved for those who were no longer with the agency, so they could not be searched.

A request for comment from the Army was not responded to. The Defense Department doesn't comment on litigation, according to an officer.

The Pentagon's response to the January 6 attack is seen as a key witness by American Oversight.

Miller, who was deposed by investigators of the riot, previously said he was never given any direction or order to deploy 10,000 National Guard troops.

McCarthy is one of the people the House select committee is interested in. The former Army secretary was "incommunicado or unavailable for most of the afternoon" on the day of the attack according to a memo written by a senior Army official.

It has recently become difficult to retrieve communications from key Trump officials and players.

When the January 6 House panel requested messages between Secret Service agents, Joseph Cuffari, who served as inspector general of the Department of Homeland Security, claimed that any correspondence was deleted as part of a pre-planning process.

The members of the January 6 committee asked Cuffari to step aside from any investigation into the Secret Service after it was reported that his office may have known about the deleted text messages earlier.