Four members of a methamphetamine operation busted recently said they had traded around 10 kilos of the drug before being arrested with 5.2 kilos.
Police in Quang Nam Province are questioning the 30-something members including one from the nearby Thua Thien-Hue Province and two from Hanoi.
They said it is possibly the biggest meth ring they ever busted and it also had connections in China.
In November 2014, they arrested the first member with 370 grams of meth and 37 grams of heroin in his body.
But the suspect kept mum until police in Thua Thien-Hue Province nearby arrested his partner two months later.
Statements from the second suspect led police to arrest the third in March this year while she was hiding at a hotel in Hanoi.
Bags of 5.2 kilograms of meth police seized from Do Chi Dung
The woman revealed the fourth suspect Do Chi Dung in Hanoi, allegedly the supplier who was arrested with 5.2 kilograms of meth.
Police said the amount of meth could have earned the gang hundreds of thousands of dollars.
It is very likely they will face death penalties.
Vietnam drug laws, some of the toughest in the world, established that those convicted of trafficking more than 600 grams of heroin or more than 2.5 kilos of methamphetamine face death penalties.
Producing or selling 100 g of heroin or 300 g of other drugs are also capital crimes.