The case is the latest scandal to hit the clergy in Buddhist-majority country, after a sex and extortion case involving senior monks last year prompted public outrage and calls for greater scrutiny of temple finances.
Phra Wachirayan Wi, the 66-year-old abbot of the 14th-century temple Wat Phutthaisawan in the ancient capital of Ayutthaya, was arrested on Thursday on charges including embezzlement and money laundering, according to the lead police investigator Pattanasak Bupphasuwan.
A 47-year-old woman accused of helping convert and conceal the money was also arrested.
Leaked CCTV footage of the pair having sex on a table in the monk’s residence was widely broadcast on Thai media.
In Thailand, Buddhist monks take a vow of celibacy and also renounce material possessions.
Police began investigating Phra Wachirayan in mid-July after receiving an anonymous tip alleging him of misconduct and misuse of temple funds.
Pattanasak, a commander of the police crime suppression division, said investigators identified two streams of money linked to donation receipts issued in the temple’s name.
About 89m baht ($2.7m or £2m) was donated for temple renovations, with another 2.8m baht in payments for Buddhist amulets and other sacred objects, he said.
“But the money from both streams did not enter the temple’s account – not a single baht,” Pattanasak told a news conference on Friday.
He said authorities had seized assets worth about 215m baht, including 16kg (35lb) of gold bars and jewellery and 28 land title deeds.
Police are investigating which are personal property and which belong to the temple.
“We will expand the investigation to identify other people involved and restore public confidence in Buddhism,” said Nattasak Chaowanasai, the commissioner of Thailand’s Central Investigation Bureau.
Wat Phutthaisawan is a prominent royal monastery with a large following that includes government officials, businesspeople, police and military personnel.
The former abbot, also known as Luang Pho Atichot, was well known for making amulets, with the Thai prime minister, Anutin Charnvirakul, reported to be among those who wore his creations.
The abbot was defrocked shortly after his arrest.
Last year, police arrested a woman accused of blackmailing at least 11 monks she had sex with, extorting nearly $12m of monastery funds from them, in a case that shook Thailand.
