Prince Andrew may have more answering to do around his former friendship with convicted sex offender Jeffrey Epstein.

According to multiple reports, U.S. prosecutors have now made a formal request to speak with Prince Andrew as part of their investigation into Epstein.

Prince Andrew stepped back from public duties last year following his alleged involvement in the Epstein scandal, which was recently the subject of four-part docuseries “Jeffrey Epstein: Filthy Rich” on Netflix.

U.K. tabloid The Sun was first to report that a Mutual Legal Assistance (MLA) request has been made at the Home Office. An MLA is a method of cooperation between states in the investigation or prosecution of criminal offences.

Prince Andrew, whom prosecutors believe could have key information that could assist an inquiry into Epstein, would be interviewed as a witness, rather than a suspect. He would also be asked to give evidence in the U.K. and wouldn’t need to be under oath.

However, if the royal refuses to cooperate with U.S. prosecutors, he may need to attend court.

Prince Andrew has denied allegations by Virginia Giuffre that he had sex with her at one of Epstein’s parties when she was 17. In November, the prince gave an interview to the BBC’s investigative program Newsnight that was widely deemed a PR disaster for Buckingham Palace, with critics accusing Prince Andrew of showing little concern for Epstein’s sex-abuse and sex-trafficking victims. He also said he did not regret his friendship with the late financier, whom he said taught him about trade and business.

In December, Buckingham Palace said Prince Andrew is “willing to help any appropriate law enforcement agency with their investigations, if required.” However, in January, U.S. Attorney for the Southern District of New York Geoffrey Berman said Prince Andrew had provided “zero cooperation” in the investigation.

Epstein committed suicide in August by hanging in a New York City jail cell, where he was being held without bail on sex-trafficking charges. Epstein was arrested on July 6, 2019, and pleaded not guilty to dozens of charges of sex trafficking for luring underage girls as young as 14 from 2002 to 2005.