According to Lang Son Province Police Department, the investigation began after authorities uncovered a narcotics possession case on March 25 in Keo Kham Hamlet, Dong Dang Commune.
The case was later transferred from the Huu Nghi International Border Gate's Border Guard Station to the provincial Drug Crime Investigation Division for further investigation.
Investigators identified the suspect as Lu ZhiShen, born in 1968, from Guangxi, China.
Lu ZhiShen at the police station (Photo: Lang Son Police).
Initial evidence included one packet of heroin weighing nearly 24 grammes, two mobile phones and several related documents.
Police later carried out an emergency search of the suspect's residence on Kim Dong Street in Dong Dang Commune.
During the search, officers seized four blocks of heroin weighing more than 1.2 kilogrammes in total, along with a nylon bag containing more than 362 grammes of narcotics and additional related evidence.
At the police station, the suspect allegedly admitted entering Vietnam through Huu Nghi Border Gate to buy drugs before storing and dividing them into smaller quantities for transport back to China for sale.
Based on the collected evidence, Lang Son Province Police upgraded the charge from illegal possession of narcotics to illegal trafficking of narcotics.
The case remains under investigation.