The House select committee investigating the Capitol riot has found gaps in official White House call logs from Jan. 6, “finding few records of calls by President Donald J. Trump from critical hours when investigators know that he was making them,” The New York Times reports Thursday.

Investigators have not, however, found evidence of tampering or deletion, notes the Times. Trump also routinely used his personal cellphone or those of his aides to make calls.

The logs given to the committee only document calls to the White House switchboard, “and any calls that were being made from the White House to others.” Trump had a habit of working around that system, “making it far more difficult to discern who he was communicating with.”

The “sparse call records” are but “the latest major obstacle” facing the panel, which is working to recreate what Trump was doing “behind closed doors during crucial moments of the assault on Congress by a mob of his supporters,” writes the Times.

Earlier Thursday, the National Archives and Records Administration requested the Justice Department look into Trump’s handling of classified information after it was revealed the ex-president brought boxes of White House records with him to Mar-a-Lago upon leaving office. It was also reported Thursday that White House staff used to occasionally find “wads of printed paper clogging a toilet and believed Trump had tried to flush it down.”