Former British royal Andrew Mountbatten-Windsor has initiated a legal challenge seeking to invalidate search warrants executed by police prior to his arrest earlier this year, the judiciary confirmed. A private hearing on the matter is scheduled to take place at the High Court in London on Thursday.

Andrew, the brother of King Charles III, contests the actions of Thames Valley Police regarding searches of his current and former residences on royal estates. The 66-year-old was apprehended on February 19, his birthday, on suspicion of misconduct in public office linked to his association with the late American financier Jeffrey Epstein. He was released on the same day but remains under investigation. Andrew has consistently denied any wrongdoing.

The police conducted searches at Sandringham, a remote royal estate in eastern England, as well as at the former Royal Lodge residence in Windsor. Legal representatives for Andrew are challenging the validity of the search warrants, which were authorized by a judge at London’s Old Bailey court, also known as the Central Criminal Court. It is reported this is the first instance since 1649, during the trial of Charles I, that a British royal has disputed the legality of criminal proceedings against them.

Thames Valley Police stated their investigation into the allegations continues and declined to comment further while the legal process is ongoing.

Andrew’s arrest and the related searches have represented a significant setback for the former prince, who was stripped of his royal titles the previous year amid fallout from his links to Epstein. Earlier this year, documents released by U.S. authorities included emails suggesting Andrew may have shared potentially confidential information with Epstein, adding to the controversy surrounding the case.