Ivanka Trump testified before the January 6 committee on Tuesday, the special congressional panel investigating the insurrection at the US Capitol in 2021 in which extremist supporters of Donald Trump attempted in vain to overturn his defeat in the presidential election.

The Mississippi congressman Bennie Thompson, the committee’s chairman, said on Tuesday afternoon that she had been answering investigators’ questions on a video teleconference since the morning and was not “chatty” but had been helpful. “She came in on her own” and did not have to be subpoenaed, Thompson said.

Ivanka Trump, who was with her father in the White House that day, is one of more than 800 witnesses the committee has interviewed as it works to compile a record of the attack, the worst on the Capitol in more than two centuries.

She is the first of Trump’s children known to speak to the committee and one of the closest people to her father.

Whether she gave the committee new information or not, her decision to cooperate was significant for the panel, which has been trying to secure an interview with her since late January.

The nine-member panel is particularly focused on what the former president was doing as his supporters broke into the Capitol and interrupted the certification of Joe Biden’s victory for several hours as lawmakers and staff fled for their lives.

The Guardian had earlier confirmed that former president Donald Trump’s oldest daughter, and former senior White House adviser, would speak to the panel virtually.

Her testimony came after that of her husband and fellow former presidential adviser, Jared Kushner, who spoke to the panel for more than six hours last week.

After Kushner’s testimony, Jamie Raskin, a Maryland Democrat and a member of the committee, told the Guardian: “There’s a momentum to this process when there’s cooperation. When people see that others are doing the right thing, it gives them the courage to do the right thing.”

A bipartisan Senate report linked seven deaths to the attack on the US Capitol on 6 January 2021, by supporters Donald Trump told to “fight like hell” in service of his attempt to overturn his defeat by Joe Biden.

Trump was impeached for inciting an insurrection but acquitted when enough Republican senators stayed loyal.

The House’s January 6 committee includes two Republicans, Liz Cheney of Wyoming and Adam Kinzinger of Illinois.

As the Guardian reported this week, the committee has identified Ivanka Trump as a senior adviser who would have known her father’s attempt to block certification of electoral college results at the Capitol was unlawful.

Referring to a law professor who presented the plan to block certification, a federal judge recently said it was “more likely than not that President Trump and Dr [John] Eastman dishonestly conspired to obstruct the joint session of Congress on January 6 2021”, and thereby committed multiple felonies.

Also in Washington on Tuesday, Enrique Tarrio, a former leader of the far-right Proud Boys group, pleaded not guilty to felony charges including conspiracy to block the certification by Congress of electoral college results on January 6.

The January 6 committee also hopes Ivanka Trump might help explain a more-than seven-hour gap in White House call logs for the day of the Capitol attack.

Ivanka Trump’s role in her father’s administration has long been a lightning rod for controversy. On Monday, the watchdog group Citizens for Responsibility and Ethics in Washington (Crew) said: “Here’s a question Ivanka Trump can answer: how did she and Jared make up to $640m while working ‘for free’ in the White House?”