A House committee investigating conservative social media site Parler on Monday demanded answers about its ownership, possible ties to Russia and whether the company offered a significant stake to former president Donald Trump to entice him to join the platform.

The letter from the House Oversight and Reform Committee cites numerous news reports about the site, which has struggled to return to full operation for weeks and which fired its chief executive last week. Parler was a fast-growing alternative to mainstream social media sites but has struggled ever since its users used the platform to instigate and celebrate the Jan. 6 assault on the U.S. Capitol.

“Since the attacks, numerous Parler users have been arrested and charged for their roles, with the Department of Justice citing in several instances the threats that individuals made through Parler in the days leading up to and following the attack,” said the committee’s chairwoman, Rep. Carolyn B. Maloney (D-N.Y.), in a statement. “Individuals with ties to the January 6 assault should not — and must not — be allowed to hide behind the veil of anonymity provided by shell companies.”

Maloney last month called for the FBI to examine the role Parler played in fomenting the Capitol assault and what ties, if any, it has with Russia. The company has used a Russian-owned Web services company, DDoS-Guard, since Amazon Web Services and other companies withdrew their technical support last month.

The letter specifically asks about this and any other ownership or other business relationships Parler may have with “any Russian individual or entity.” The request also seeks information about a report in BuzzFeed News last week about negotiations between Parler and Trump over the possibility of his taking an ownership stake in the company.

Twitter kicked Trump off its platform two days after the Capitol attack, and he has expressed interest in finding a new social media home but has not done so. He had 88 million followers on Twitter, and his account was central to his political power and his ability to drive news coverage toward issues of his choosing.

One issue cited in the previous letter from the House committee, involving the Parler chief executive’s marriage to a Russian woman, appears to remain of interest to the committee even though the company fired the executive, John Matze, last week.