A Cambridgeshire man paid an undercover US agent for sex with a nine-year-old boy, according to US federal prosecutors. Paul Charles Wilkins, of Littleport, Cambridgeshire, volunteered at Ely Cathedral and the Salvation Army, travelled to California in January to meet young boys for "illicit sexual conduct" according to prosecutors. The 70-year-old, who holds dual UK and US citizenship, is also accused of attempted sex trafficking of children.

Wilkins was caught in an undercover operation when a US agent communicated with him on an online group administered by Wilkins which is allegedly used by those with a "sexual interest in children", according to the BBC. The group described itself as "a safe place for dads and sons who enjoy relations".

Court documents show that Wilkins took a laptop containing pornographic images with him from the UK to the US. Using a false name, Wilkins told the US undercover agent that he had come to California after the father of two young boys, said he could have sex with his children.

A second undercover agent was brought in as a "pimp", purportedly offering Wilkins a nine-year-old Mexican boy whose family was in debt.

US federal prosecutor Eileen Decker said: "Child predators – whether foreign or domestic – threaten the most vulnerable members of society, which is why we devote considerable resources to stopping them. "The new indictment adds additional charges that… could subject him to a longer prison term."

The investigation was led by agents from the US Immigration and Customs Enforcement's Homeland Security Investigations (HSI) department. The national task force aimed at finding child predators has arrested 238 people in less than two months in Southern California, according to ABC News. According to the Los Angeles Police Department, the Internet Crimes Against Children (ICAC) task force carried out Operation Broken Heart II in April and May.

Robert Goetsch, acting special agent in charge for HSI Los Angeles, said: "Paedophiles in the United States, or anywhere in the world, who believe they can escape the detection of law enforcement by travelling to another country to commit heinous crimes against children should take note.

"HSI and its law enforcement partners around the globe will pursue those criminals who subject children to this torment and bring them to justice by using every tool at our disposal." Wilkins will face trial in the US on 19 July.

In 2011, Wilkins was convicted of possessing and distributing thousands of pornographic images featuring children as young as nine months. During sentencing, Judge Hawkesworth told Wilkins: "It's one of the worst cases this court has experienced. You have been able to place yourself in a fantasy world and in which you have abandoned any moral sense whatsoever."

The Cathedral volunteer was given a prison sentence of 56 months, and had to serve half, according to Cambridge News. Wilkins was on probation when he entered the US.