Thailand's Crown Prince Vajiralongkorn has asked the government to strip his wife's family of their royally issued surname, the latest development in a high-profile crackdown that involves senior members of the police force.

The move came after at least three of Princess Srirasm's relatives were arrested as part of the probe.

In a letter dated Friday but released over the weekend, the crown prince ordered the "cancellation of the royally bestowed family name 'Akrapongpreecha,'" which was issued after the pair married in 2001. The letter was sent to the Interior Ministry.

Srirasm is the crown prince's third wife. They have a 9-year-old son.

Last week, eight senior police officials were arrested on charges ranging from bribery to insulting the monarchy.