Thames Valley Police said it arrested a 66-year-old man on suspicion of misconduct in public office, which carries a maximum sentence of life imprisonment in the United Kingdom.

The police force, which covers an area in southern England where Andrew Mountbatten-Windsor used to live, did not name him, as is standard practice under British law. Asked whether Mountbatten-Windsor had been arrested, the police responded with a statement.

“We understand the significant public interest in this case, and we will provide updates at the appropriate time,” Assistant Chief Constable Oliver Wright said. “Following a thorough assessment, we have now opened an investigation into this allegation of misconduct in public office.”

Police said they were searching two addresses in Berkshire and Norfolk. Andrew lived in Windsor's Royal Lodge in Berkshire until earlier this month; his new home on the Sandringham Estate is in Norfolk.

Earlier, news photographers captured what appeared to be unmarked police cars arriving at Andrew's home in Sandringham.

Mountbatten-Windsor has always denied any wrongdoing in connection to his affiliation with Epstein, and said he regrets the friendship.

It caps years of growing pressure on Andrew, the brother of King Charles III and son of the late Queen Elizabeth II, over his yearslong friendship with Epstein, the late convicted sex offender and financier.

It is extremely rare for a senior member of the royal family to be arrested.

In 2002 Princess Anne, the sister of the king and Mountbatten-Windsor, was convicted under the Dangerous Dogs Act after her English bull terrier, Dotty, bit two children while walking in Windsor Park.

British media said at the time it was the first instance of a royal being convicted of a criminal offence.

(NBC NEWS)