As Alaskan man has been sentenced to 18 years behind bars for attempting to arrange a child sex tourism trip to Cambodia for himself and others, and for sexually exploiting children in Cambodia over a four-year period, the US Justice Department announced on Friday.

Jason Jayavarman, 45, was found guilty and convicted of the crimes in March last year, after an anonymous tip-off triggered an FBI and police investigation, said a statement from the department.

According to trial evidence, he planned a trip for himself and others to engage in illicit sexual conduct with Cambodian children as young as 12.

Jayavarman told potential clients – including an undercover FBI agent – how to groom a child for sex and avoid arrest.

Trial evidence also proved he made 12 trips to Cambodia between 2010 and his arrest in 2013, where he made multiple pornographic videos of himself engaging in sexual acts with someone he believed to be a child.

US district judge Sharon Gleason of the District of Alaska on Thursday sentenced Jayavarman to 18 years’ jail and a lifetime term of supervised release.

Nget Thy, executive director at the Cambodian Centre for the Protection of Children’s Rights, said the sentence “set an example” to opportunistic foreigners angling to exploit children in the Kingdom.

“The children are very vulnerable, especially the poor … it is happening more and more in Phnom Penh,” he said.

“It is very easy for them to be exploited, so we have to protect them.”