In Andrew Mountbatten-Windsor's dramatic arrest, an anti-monarchy group is taking credit, claiming their efforts led the authorities to nab him.
But Graham Smith, the group's Republic CEO, is indicating the action against the former prince is just a start in dealing a blow to the monarchy's roots.
He is calling for the investigation's scope to widen, suggesting King Charles and Prince William might be privy to materials that could lead the authorities to put them on notice.
"There is reason to believe that in relation to some offences other senior royals may be material witnesses and may have also committed offences," he tells Newsweek.
Smith continues, "Now the police must follow all evidence wherever it leads and that the King and Prince William need to speak up and admit to whatever they have known, when and why they continued to protect Andrew."
On his account on X, the anti-monarchy head has also tweeted, "Charles and William have questions to answer."
Meanwhile, Thames Valley Police swooped on Sandringham Palace in the morning to arrest Andrew over suspicion that he may have misused his authority while serving as the UK's trade envoy from 2001 to 2011.