Investigators have found an eight-hour gap in Donald Trump’s official phone records as thousands of his supporters stormed the US Capitol, according to a person familiar with the inquiry.

It is widely known that Mr Trump, the president at the time, had conversations with multiple Republican politicians on the day of the insurrection on 6 January 2021.

Mr Trump’s supporters stormed the building as a joint session of Congress was sitting to ratify Joe Biden’s election as president.

A judge ruled earlier this week that the former president “more likely than not” committed a crime when he tried to obstruct Congress and overturn his election defeat.

The gap in his official phone records extends from shortly after 11am to around 7pm local time, the source told the Associated Press on condition of anonymity.

House select committee investigators are looking into whether Mr Trump was communicating through other means during this period, possibly through personal mobile phones, burner phones or some other type of communication, such as a phone passed to him by an aide.

A burner phone is a cheap pre-paid device that is typically destroyed after use. They are often used by criminals.

The House panel’s findings raise questions over whether Mr Trump purposefully circumvented official channels to avoid creating records.

The committee has subpoenaed mobile phone companies for records and is awaiting data.

The panel is also continuing to receive records from the National Archives and other sources, which could produce additional information.

The lack of information about Mr Trump’s calls is a challenge to investigators as they try to create the most comprehensive record yet of the attack, with a particular focus on what the president was doing in the White House as it happened.

During the missing hours, Mr Trump spoke at a rally near the White House before watching as the violent mob broke into the US Capitol.

The rioters overwhelmed police and marauded through the building for hours before they were finally kicked out and the building declared secure at about 5:30pm local time.

More than 700 people have been arrested over the violence, which left five people dead, including one police officer.

The committee is focused on Mr Trump’s actions that day because he waited hours to tell his supporters to stop the violence and leave the Capitol.

The panel is also interested in the organisation and financing of a rally that morning where Mr Trump told his supporters to “fight like hell”.

Among the unanswered questions is how closely organisers of the rally coordinated with White House officials.

In many cases, the committee may not need direct confirmation from the White House about Mr Trump’s calls.

Politicians have already interviewed more than 500 witnesses, including several people in Mr Trump’s inner circle who may be able to fill in those gaps.

They are hampered, however, by the former president’s claims of executive privilege over his personal conversations, which have prompted many witnesses to refuse to answer some questions.

Committee members voted unanimously on Monday to hold former Trump advisers Peter Navarro and Dan Scavino in contempt of Congress for their months-long refusal to comply with subpoenas.