A Big Island man accused of having sex with a 12-year-old girl in Cambodia pleaded guilty yesterday to a federal sex tourism charge.

Richard David Mitchell, 61, of Waimea agreed to plead guilty in exchange for a three-year, 10-month prison sentence in a deal with federal prosecutors. The maximum prison term for the crime is 30 years.

Mitchell also faces a maximum $250,000 fine, lifetime supervision after his release from prison and mandatory restitution when he is sentenced in February.

He admitted yesterday to having sex with a prostitute, specifically one at least 12 but less than 16 years old, on Aug. 28 last year.

Federal authorities said two people saw Mitchell have sex with the girl on the back of a motorbike and on a street curb in Phnom Penh. One of the witnesses called Cambodian police, who arrested Mitchell.

Mitchell remained in a Phnom Penh prison until Cambodian authorities returned him and three other Americans accused of similar crimes to the U.S. in August. He returned to Hawaii in September.

As part of his plea deal, Mitchell will not get credit for the year he was in Cambodian custody.