A US lawmaker has made a direct plea to Sarah Ferguson to testify about her 'close personal and business ties' to Jeffrey Epstein, according to a letter seen exclusively by the BBC. Congressman Suhas Subramanyam urged her to provide information to the US congressional committee investigating the late sex offender. He also asked for any knowledge she had of her ex-husband Andrew Mountbatten-Windsor's involvement in Epstein's operations. The letter represents the most direct pressure on the former duchess to testify since the start of the Epstein scandal. Ferguson's representatives have been approached for comment. Mountbatten-Windsor has denied any wrongdoing in relation to Epstein. Mountbatten-Windsor has not responded to the BBC's requests for comment on the specific allegations in relation to the release of millions of Epstein files in January. At the weekend, the BBC first revealed that some US lawmakers were calling for Ferguson to give evidence concerning her links to Epstein. There is no legal mechanism to compel the former duchess to testify in the US. In the letter, which was sent to Ferguson on Thursday and set a two-week deadline for her to respond, Congressman Subramanyam, a member of the House Oversight Committee, said the recent drop of Epstein files by the US Department of Justice had revealed her 'close personal and business ties' with the American financier. 'As the committee seeks justice for the survivors of Mr Epstein's criminal enterprise, and transparency for the American public, I respectfully request your cooperation with the committee's investigation,' he wrote. The letter referred to an email from a 'Sarah' describing Epstein as 'a legend' after his conviction in 2008 for soliciting prostitution from a minor and it was written: 'I am at your service. Just marry me.' It also referenced emails that suggest Ferguson asked Epstein directly for financial assistance. 'Additionally, while you officially divorced former Prince Andrew in 1996, the committee is interested in learning more about any knowledge of Mr Mountbatten-Windsor's involvement in Mr Epstein's operations,' the letter said. 'It is clear that you possessed social and business ties to Mr Epstein and have knowledge of information that can assist our investigation.' Subramanyam has stated that although there is no legal obligation for Ferguson to comply, her cooperation is crucial for the ongoing investigation into Epstein's network. If Ferguson knows anything, she should testify in the United States immediately,' a representative for Giuffre's brother Sky Roberts told the BBC. Ferguson has already suffered fallouts over her links to Epstein, losing several charity positions and her honorary title from the city of York due to the scandal.