A house fire killed three family members early Friday morning in Long An Province's Can Duoc District.
Long An police have requested help from the Ministry of Public Security to determine the cause of the fire, calling the situation "complicated."
The fire broke out at around 1 a.m.in Can Duoc's Long Dinh Commune at the home of Nguyen Hoang Phuong, 64, killing Phuong, his wife, Nguyen Thi Hong, 54, and Nguyen Thanh Duy, Hong's 13-year-old son from a previous marriage.
Their neighbor, Le Van Thanh, told Vietnam News Agency that he heard the crackling of a fire and ran out of his house to find Phuong's house ablaze.
He asked for help from other neighbors to break into the burning house in an attempt to save the victims.
Simultaneously, Duy's sister, Nguyen Thi Cam Nhung, emerged from behind the house, also calling for help.
Hong, Phuong and Duy died before the fire could be extinguished.
Senior Lieutenant Colonel Nguyen Van Duc, a spokesman for the Long An Police Department, told VnExpress that some witnesses said they heard minor explosions they thought came from the house.
Nguyen Hoang Minh, another son of Hong and her first husband, said his mother had six children before divorcing his father and marrying Phuong several years ago.
He and other siblings live in Ben Luc District, while Nhung and Duy had been staying with their mother and stepfather.