He was defrocked amid accusations he had sexual relations with women – a major violation of the precepts guiding monks' behaviour – and had impregnated one. He fled to the US, where he was arrested in 2016 and extradited last year.
On Wednesday, Ratchada Criminal Court in Bangkok handed Wirapol two eight-year prison terms, one for violating a minor under 15 and another for rape.
Wirapol is already serving a lengthy prison sentence. In August, the same court sentenced him to 114 years in connection with funds he fraudulently raised from followers.
He was found guilty of fraud, money laundering and violation of the computer crime act for taking money he had solicited for Buddhist statuary and temple improvements and spending it on cars and luxury goods.
Legal technicalities capped the 114-year sentence at 20 years, meaning he will now serve 36 years.
Wednesday's court ruling said prosecutors charged that Wirapol abducted a 13-year-old girl and sexually assaulted her from January 2000 to the middle of 2001, during which time she became pregnant.
The victim, now 32, said she was satisfied with the sentencing. She said she would present the ruling to Sisaket Juvenile and Family Court, where she has filed a lawsuit against Wirapol requesting 40 million baht (£936,000) in child support in a case the court had put on hold pending Wednesday's ruling.
She said Wirapol had initially provided her 10,000 baht (£234) per month to take care of their child but he gradually stopped the payments.
According to Thailand's Department of Special Investigation, Wirapol at one point had accumulated assets estimated at 1 billion baht (£23m). During a shopping spree from 2009 to 2011, he bought 22 Mercedes Benz cars worth 95 million baht (£2.2m), the department said.
An earlier civil court ruling ordered the confiscation of 43.5 million baht (£1m) from Wirapol.
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