Bangkok Post reported Manas Kongpan, who had hypertension, high cholesterol and bradycardia, had a heart attack while exercising on the 8th floor of the hospital.

“Manas was pronounced dead at 8pm on Wednesday,” the report said.

Manas, 65, was convicted with other officials and dozens of Thai nationals after a lengthy trial which began in 2015, after a crackdown following the discovery of dozens of shallow graves in a jungle near the Thai-Malaysian border.

On May 2015, more than 130 graves were discovered in 28 temporary camps that were run by a human trafficking syndicate in Wang Kelian, Perlis.

In 2017, the criminal court sentenced Manas to 27 years jail on different charges including trafficking in persons, smuggling illegal migrants into the country and organised crime.

Apart from Manas, the criminal court sentenced 62 defendants including the former mayor of a subdistrict of the southern Songkhla province, Banjong Pongphon to 78 years in prison.

A businessman and former administrative body chief of Satun province Pajjuban Angchotephan was also jailed for 75 years.

In 2019, a Thai court of appeal increased the prison time for Manas from 27 years to 82 years for trafficking and corruption.