Emails suggest that the late sex offender Jeffrey Epstein invited a man believed to be Andrew Mountbatten-Windsor to have dinner with a 26-year-old Russian woman.
The latest batch of documents released by the US Department of Justice relating to Epstein shows emails signed "A", with a signature that appears to read "HRH Duke of York KG".
The emails were exchanged in August 2010, two years after Epstein pleaded guilty to soliciting a minor.
The messages are likely to put further pressure on Mountbatten-Windsor, who has faced years of scrutiny over his past friendship with Epstein.
BBC News has approached Mountbatten-Windsor for comment. He has repeatedly denied any wrongdoing.
