The British founder of a Cambodian orphanage is facing prosecution for sexually assaulting a boy in his care.
Nicholas Griffin, 52, was held when police raided his isolated base in countryside near Siem Reap, in the north-west of the country.
Up to 100 children were moved to a safe house in an operation that involved British and local investigators.
Mr Griffin, originally from Wales, left Britain in 2006 before founding the Cambodia Orphan Fund, one year later.
He faces a potential 10-year jail sentence over a claim he sexually assaulted a 15-year-old boy.
He was originally held on suspicion of breaking child labour laws and his orphanage licence.
The orphanage manager, a Cambodian man, has been charged with the illegal removal of a child to the orphanage.
Jim Gamble, of the Child Exploitation and Online Protection Centre (Ceop), said Cambodian police are now examining claims of "institutional abuse" within the orphanage, which occupies an unusual fortress-like building.
Mr Gamble added: "The UK and Cambodia may have different legal systems and law enforcement practices, but we share a clear, joint commitment: to prevent harm to children."
He said the operation demonstrated the value of the organisation's international child protection network.