Nguyen Thi Hong Bich, 38, was arrested on July 5 after a nephew of her was confirmed to have been poisoned with cyanide by the police.
Upon her detention, Bich confessed that due to conflicts with family members, she had bought cyanide to poison her 18-year-old nephew, who lives in the same house with her in Nhon Trach District.
The teenager, fortunately, has been out of critical condition and is still hospitalized.
Over two days of investigation, Bich admitted on Sunday besides using cyanide to poison that nephew, she had killed his younger brother, a niece who was her sister's kid, and her husband between October last year and May this year.
She used cyanide in all cases.
According to the police, Bich and her husband lived in the same house with her elder brother, his wife and two sons in a single-story house in Nhon Trach.
Together, they ran a restaurant.
On Oct. 14, 2023, believing her 38-year-old husband was gambling and in debt, Bich added cyanide to his daily medication and gave it to him. He died four days later. The family thought he must have died of a stroke or a heart attack.
After her husband's death, Bich was angry because her sister accused her of having an affair, so she poisoned the sister's seven-year-old daughter late last year. Once again, no one in the family suspected foul play.
By the end of May, after having some arguments with her brother's wife, Bich poisoned their youngest son, who was 12.
Most recently, due to disagreements over home repairs and buying a new sink to serve the restaurant, Bich plotted to kill her brother's oldest son, the 18-year-old, for revenge.
On June 22, while the teenager was studying alone at home, Bich approached him and commented on his acne-ridden face.
She mentioned that she used to have the same problem and had taken some processed herbs to detoxify.
The young man trusted her aunt and agreed to use the herbs.
Bich Then visited a nearby pharmacy, lying that she needed to buy some medicine for her leg pain.
Then she emptied the medicine from a capsule, replaced it with cyanide, and gave it to her nephew.
Shortly after, Long became drowsy and was found by his mother, who rushed him to Le Van Thinh Hospital in Ho Chi Minh City, which borders Dong Nai.
Doctors conducted tests and found cyanide in the patient's body.
His family reported the case to the police and an investigation led to Bich.
A police search found white plastic bottle weighing about 0.7 kg containing cyanide crystals, which Bich had hidden in a nearby cemetery.
The criminal technical department of Dong Nai Police confirmed that this substance was highly toxic cyanide.
Investigators determined that Bich owed money to several people. After her husband died, Bich received VND800 million from insurance, which she used to pay off debts and spend.
Aside from the four family members that Bich admitted to have poisoned, her father and her own child had also passed away unexpectedly.
Bich’s father, Hai, died shortly after her husband and because the old man had many chronic diseases, no questions were raised.
Next was Bich's 14-year-old child. The child died quickly with symptoms such as difficulty breathing, cardiac arrest, and cyanosis all over the body.
Her neighbor reported that when the child developed those symptoms, Bich kept hesitating and did not call an ambulance.
Police are expanding the investigation.