Dressed in a bullet-proof strait-jacket and flanked by commandos wielding automatic weapons, Li was escorted on to a US Air Force flight for New York, where he will stand trial on charges of shipping 486kg of pure heroin from Burma. The narcotics, with an estimated street value of $122m (pounds 75m), were seized by Californian customs officials in 1991.
For years the close confidant of the Burmese opium warlord, Khun Sa, Li Yun-chung - a Burmese born ethnic Chinese with residency in Thailand - was at the centre of "Golden Triangle" heroin production in South-east Asia. His indictment for trafficking in the US made him one of the world's most wanted men until his high-profile arrest in Bangkok last year.
The controversial decision by a senior Thai judge, Somchai Udomwong, to grant Li bail during an unscheduled hearing led to widespread allegations of bribery. The allegations intensified when Li jumped bail and escaped to Burma to avoid extradition to America.
He was eventually returned to Thai custody last month, fuelling political controversy by threatening to go on record saying exactly how he was granted bail.
"This is becoming extremely embarrassing for the Thai government," said one diplomat.