Top officials at the Department of Homeland Security (DHS) inspector general’s office interfered with efforts to recover erased Secret Service texts from the time of the US Capitol attack and attempted to cover up their actions, two House committees said in a letter on Monday.

Taken together, the new revelations appear to show that the chief watchdog for the Secret Service and the DHS took deliberate steps to stop the retrieval of texts it knew were missing, and then sought to hide the fact that it had decided not to pursue that evidence.

The inspector general’s office had initially sought to retrieve the lost texts from across the DHS – spanning both the Secret Service as well as the former DHS secretary Chad Wolf and his deputy, Ken Cuccinelli – as part of its internal review into January 6.

But six weeks after the inspector general’s office first requested Secret Service communications from the time of the Capitol attack, that effort was shut down by Thomas Kait, the deputy inspector general for inspections and evaluations, the House committees said.

“Use this email as a reference to our conversation where I said we no longer request phone records and text messages from the USSS relating to the events on January 6th,” Kait wrote in a July 2021 email to a senior DHS liaison official, Jim Crumpacker, that was obtained by Congress.

The House committees also disclosed they had learned that Kait and other senior officials manipulated a memo, authored on 4 February 2022, that originally criticized the DHS for refusing to cooperate with its investigation and emphasized the need to review certain texts.

By the time that Kait and other senior officials had finished with the memo, the House committee said, mentions about the erased texts from the Secret Service or the DHS secretary had been removed and instead praised the agency for its response to the internal review.

The memo went from being a stinging rebuke that said “most DHS components have not provided the requested information” to saying “we received a timely and consolidated response from each component”, the House committees said.

Appearing to acknowledge the removal of the damaging findings in the memo, Kait asked colleagues around that time: “Am I setting us up for anything by adding what I did? I spoke with Kristen late last week and she was ok with acknowledging the DAL’s efforts.”

The disclosures alarmed the House oversight committee chair, Carolyn Maloney, and House homeland security committee chair, Bennie Thompson – who also chairs the House January 6 committee – enough to demand that top DHS officials appear for transcribed interviews.

In the four-page letter, the two House committees again called for the recusal of the DHS inspector general, Joseph Cuffari, and demanded communications inside the inspector general’s office about not collecting or recovering texts from the agency relating to the Capitol attack.

The deepening investigation has also revealed that Cuffari’s office was notified in February 2022 that texts from Wolf and Cuccinelli could not be accessed and that Cuccinelli had been using a personal phone – yet never told Congress.

Kait has a history of removing damaging findings from reports. In a DHS report on domestic violence and sexual misconduct, Kait directed staff to remove a section that found officers accused of sexual offenses were charged with generic offenses, the New York Times reported.

The controversy over the missing texts erupted several weeks ago after Cuffari first informed Congress in mid-July that his department could not turn over Secret Service texts from the time of the Capitol attack because they had been erased as part of a device replacement program.

That prompted Thompson, through the House January 6 select committee, to issue a subpoena to the Secret Service for texts from the day before and the day of the Capitol attack as it examined how the agency intended to move Donald Trump and Mike Pence on January 6.

But the Secret Service provided only one text exchange to the select committee, the Guardian has previously reported, telling investigators that every other message had been wiped after personnel failed to back up data from the devices when they were swapped out.