By Agence France-Presse
Thai cops arrested Alexandre Cazes in Bangkok on July 5 and had planned to extradite him to the US, where he faced drug trafficking and money laundering charges.
But the computer programmer hanged himself with a towel in his detention cell on July 12, according to Thai anti-narcotics police, who have been tight-lipped on the details of his case.
On Saturday a Thai officer confirmed Cazes was wanted in the US for running a massive online black market.
"It's huge dark web market that trafficks drugs and sell other illegal stuff," the police officer said, requesting anonymity.
Speculation is rife that the underground marketplace was AlphaBay, considered the world's largest and most lucrative darknet bazaar until it was taken down within hours of Cazes arrest.
Like its predecessor Silk Road, which was shut down by authorities in 2013, AlphaBay used Tor technology and crytocurrencies like Bitcoin to shield customers from detection.
According to Nicolas Christin, a computer science professor at Carnegie Mellon University, AlphaBay gained prominence in 2015 and mostly traded in drugs, stolen credit card numbers and forged IDs.
It was "more than twice as big as Silk Road was in its heyday, with a revenue of somewhere between 600,000 and 800,000 dollars a day in early 2017, and that's a rather conservative estimate," he told AFP.
Cazes appeared to be living a life of luxury in Thailand, where he owned three houses and four cars -- including a Lamborghini -- according to Thai police who have seized the assets.
"Cazes slipped into Thailand seven to eight years ago," said Major General Chayapot Hasunha from Thailand's Narcotics Suppression Bureau.
Thai authorities obtained an arrest warrant for the Canadian, who had a Thai wife, after the US requested his extradition.
The US Embassy in Bangkok refused to comment on the details of the case, saying only that Cazes was detained based on a request from the US "with a view toward extradition to face federal criminal charges".