LONDON — King Charles’ younger brother Andrew Mountbatten-Windsor was arrested on suspicion of misconduct in public office this week, over allegations that he sent confidential British government documents to disgraced financier Jeffrey Epstein.

Thames Valley Police, whose detectives questioned the former prince all day on Thursday, have said they are looking into allegations that Mountbatten-Windsor had passed documents to the late convicted US sex offender while working as a trade envoy.

Among files relating to Epstein released by the US, some suggest that Mountbatten-Windsor forwarded to Epstein in 2010 reports about potential business opportunities in places he had visited as the Special Representative for Trade and Investment.

The former prince, who turned 66 on Thursday, has always denied any wrongdoing in relation to Epstein. He was released from custody late on Thursday while the investigation continues.