nation to tell them to stop this. reporter: the january 6 committee is now investigating whether the president and top aides used so-called burnero disposable phones to avoid scrutiny of their calls during that time. it s almost like they didn t want this out there, and so, we need to get to the bottom of this. reporter: the logs do show several calls on the morning of the 6th, including from rudy giuliani and former president trump s chief strategist steve bannon. at 8:37 a.m., trump spoke with bannon, who sources say told him to call vice president mike pnce and urge him to block certification of the election. trump later did phone pence, failing to persuade him, but that call is not noted in the records. there is a listing at 11:17 a.m., the president talked in a phone call to an own identified person. cbs news has learned the pence call was in that time frame. there is also a lengthy gap during the attack as recorded in mr. trump s daily diary.