King Charles III voiced his “deepest concern” regarding the Thursday morning arrest of his brother, Andrew Mountbatten-Windsor, who is suspected of misconduct in public office.

“The next steps involve a complete, fair, and proper process where this matter will be investigated appropriately by the relevant authorities. As I’ve stated previously, they have our full and unreserved support and cooperation,” Charles said in a statement released by Buckingham Palace to TIME.

Stressing that “the law must take its course,” Charles added: “While this process unfolds, it would be inappropriate for me to make additional comments on the matter. In the meantime, my family and I will carry on with our duties and service to all of you.”

The King’s statement was issued shortly after Thames Valley Police carried out early-morning searches at two locations linked to Andrew.

“Today, we arrested a man in his 60s from Norfolk on suspicion of misconduct in public office and are conducting searches at addresses in Berkshire and Norfolk,” a police statement noted. “The individual is currently being held in police custody.”

Following U.K. guidelines, the police force said it will “not disclose the name of the arrested individual.”

When TIME asked Thames Valley Police to confirm whether Andrew, 66, had been arrested, the force directed the publication to its earlier statement.

“After a comprehensive review, we have launched an investigation into this claim of misconduct in public office,” said Assistant Chief Constable Oliver Wright, who acknowledged the public’s interest in the case. “We must safeguard the integrity and impartiality of our investigation as we collaborate with partners to look into this alleged offense.”

Norfolk Police told TIME it is assisting Thames Valley Police with the investigation.

TIME has contacted Andrew’s representatives to request a comment.

Reports of the arrest emerged after unmarked police cars and plainclothes officers were spotted arriving at Andrew’s current residence—Wood Farm on the royal Sandringham Estate in Norfolk, U.K.—early Thursday morning. The searches took place on Andrew’s 66th birthday.

The details of the allegations that led to Andrew’s arrest have not been made public yet.

On February 9, Thames Valley Police had previously told TIME they were “evaluating information” about claims that Andrew—during his tenure as the U.K.’s trade envoy—shared confidential government reports with Jeffrey Epstein, the late convicted sex offender. These reports detailed trips to Singapore, China, Hong Kong, and Vietnam between 2010 and 2011.

These allegations originated from recently revealed communications between Andrew and Epstein, which were included in the U.S. Department of Justice’s final release of Epstein-related documents on January 30.

A message initially sent to an individual addressed as “The Duke”—and later forwarded to Epstein—reads: “Please find attached the visit reports for Vietnam, Singapore, Hong Kong, and Shenzhen regarding your recent trip to Southeast Asia.”

Another communication from “The Duke” to Epstein seemed to outline an investment opportunity in Afghanistan.

Before losing his royal titles last year, Andrew was known as the Duke of York.

The DOJ-released documents also contained a photo of Andrew leaning over a woman on the floor. The woman’s face was redacted, and the time or location of the photo’s capture is unknown.

This image was shown on a screen in the background during U.S. Attorney General Pam Bondi’s testimony before the House Judiciary Committee on February 11, where she discussed the DOJ’s handling of the Epstein files.

Authorities were also examining a new claim that Epstein arranged for a woman to visit Andrew at his Royal Lodge home in Windsor in 2010.

“We have received reports of a woman allegedly taken to a Windsor address in 2010 for sexual activities,” a Thames Valley Police spokesperson told TIME on February 4. “We are evaluating this information in accordance with our standard protocols.”

These new allegations against Andrew have raised fresh questions about his relationship with Epstein and his personal behavior.

Andrew has repeatedly and firmly denied any improper conduct.

Buckingham Palace had earlier stated that King Charles would cooperate with police if contacted, as they investigate claims involving his brother and his connections to Epstein.

“While Mr. Mountbatten-Windsor is responsible for addressing the specific claims in question, we are prepared to assist Thames Valley Police if they reach out to us—just as you would anticipate,” a February 9 statement noted. The Palace repeated this position on Thursday.

Before news of Andrew’s arrest broke, British Prime Minister Keir Starmer stated that “nobody is above the law” when queried about whether the royal should testify before the U.S. Congress.

“Anyone with relevant information should testify—whether it’s Andrew or someone else,” he told the BBC, repeating remarks he made in an interview aired earlier that week.

This is an ongoing story and will be updated as more information becomes available.