A Canadian citizen living in Thailand has been arrested in London on U.S. charges of international sex tourism.

John Wrenshall, 62, was named in an 18-count indictment handed up by a federal grand jury in New Jersey in August and unsealed with his arrest Monday at Heathrow Airport by London police and U.S. Immigration and Customs Enforcement officials.

According to the indictment, Wrenshall helped arrange trips to his home in Thailand during which U.S. citizens and others paid to engage in oral sex and other sexual acts with Thai boys, some as young as 4 years old.

Authorities say three of Wrenshall’s clients, including 59-year-old Wayne Nelson Corliss, have pleaded guilty to sex tourism and other charges. Corliss was arrested in Union City, N.J., in May after being identified in a photograph circulated by Interpol.

Wrenshall is charged with one count of conspiracy to engage in sex tourism, two counts of aiding and abetting sex tourism, one count of conspiracy to produce child pornography, seven counts of production of child pornography and seven counts of distribution of child pornography.

Each count of sex tourism carries a maximum penalty of 15 years in prison. Each count of production of child pornography carries a maximum penalty of 10 years, and each count of distribution of child pornography carries a maximum of 15 years.

Wrenshall is being detained pending extradition from the United Kingdom. It was not immediately known if he had retained a lawyer.