Chinese police had issued a special warrant to arrest the four men, between 30 and 52 years of age, for illegal trading of goods and smuggling of solid waste.

Vietnamese police under the Ministry of Public Security handed the wanted men over to Chinese police on Monday at the border gate in Cao Loc District, Lang Son Province.

According to Chinese anti-smuggling police, one of them set up the ring in 2017 and had the other three smuggle 242 tons of edible bird’s nests worth 2 billion yuan ($290 million) from the Vietnam-China border area to Indonesia and Malaysia, evading 590 million yuan ($85.3 million) in taxes.

After learning that they moved in Vietnam in April, they asked Vietnamese police for help in tracking them down.

Vietnamese police arrested the four in Lang Son Province last Thursday.