Police in the northern province of Quang Ninh on Monday began investigating the collapse at an illegal coal mine that killed two people on August 20.
The mine was run by Nguyen Tien Sy, who was fined VN12.5 million (US$600) on August 14 for illegal mining, according to investigators.
Local agencies then also closed the mine down. However, a group of miners still entered it. It is still unknown if this group was related to Sy.
The mine collapsed on Saturday due to landslides caused by recent heavy rains, burying two people.
At around 11.30 p.m. Sunday, local rescuers discovered the bodies of the victims, who were later identified as Nguyen Van Binh (1955) and Vu Van Ty (1984).
Police said they are now investigating a man named Nguyen Quoc Thinh, who allegedly led the group of miners to the site.