Prince Andrew leaves St. Giles Cathedral after the arrival of the coffin containing the remains of his mother Queen Elizabeth, in Edinburgh, Scotland. (Photo: AP) Andrew Mountbatten-Windsor was released hours after being arrested on suspicion of misconduct in public office, according to news website BBC.
Andrew, however, remains under investigation. He was questioned on Thursday and later allowed to leave custody while inquiries continue.
The investigation stems from claims that, while serving as a UK trade envoy, he passed confidential government documents to Jeffrey Epstein, a relationship documented in files released by the US government. He has consistently denied any wrongdoing.
Thames Valley Police said a formal investigation was opened following what it described as a “thorough assessment” of allegations of misconduct in public office.
The force has been reviewing claims connected to Andrew’s association with the late US sex offender Jeffrey Epstein. Officers were examining whether confidential information may have been shared during the period Andrew carried out official duties.
Police have said the arrest is not related to any allegations of sexual offences.
Andrew was arrested at Sandringham at about 08:00 GMT and taken to Aylsham police station in Norfolk for questioning.
The Guardian reported that officers carried out searches at Wood Farm on the Sandringham estate and at the Royal Lodge in Windsor.

In an updated statement, Thames Valley Police confirmed he “had been released under investigation” and said searches in Norfolk had been completed. Searches at the Berkshire address were continuing at the time of the update.
King Charles III said “the law must take its course” following the arrest.
In a statement the King said, “What now follows is the full, fair and proper process by which this issue is investigated in the appropriate manner and by the appropriate authorities.”
He added that the police have his “full and wholehearted support and co-operation”.
Thames Valley Police said it is important to protect “the integrity and objectivity” of the investigation and that further updates will be provided when appropriate.
Earlier in February, the force also said it was assessing a separate allegation that a woman was sent to the UK by Epstein in 2010 for a sexual encounter with Andrew.