Authorities in China have broken up a massive cross-border online gambling ring they claim handled over $78b in wagers from nearly one million customers.

On Tuesday, China’s Ministry of Public Security announced that it had arrested 98 suspects involved in a network of over 500 betting websites. Police said the investigation, dubbed Operation 109, had begun rounding up the conspirators in July but official word is only now emerging.

Police said their investigation began in August 2014 when an officer in Hunan province caught one bettor logged on to a betting site via an internet café. In March 2015, police formed a special investigation team to track down the ringleaders. A 40-year-old Guangdong resident named Xu has been fingered as the operation’s top man.

The operation reportedly based its main servers in Taiwan, although the technical team was run from a mainland technology firm in Shenzhen, while customer service teams operated out of Hong Kong, Thailand and the Philippines. China’s ‘renegade province’ Taiwan has been cooperating with mainland authorities on similar busts since 2013.