Nguyen Thi Hong Bich, 38, was first arrested by the police of southern Dong Nai Province on July 5 for the suspected poisoning of her 18-year-old nephew Long.
Bich confessed that besides poisoning Long, who had been discharged from the hospital, she had also used cyanide to poison and kill her own husband, a niece and another nephew.
She said that in October last year, she saw that her husband was "addicted to gambling" and harming the family's finances. As her husband did not listen to her advice, Bich said she wanted to kill him so he "would not bother her."
She bought cyanide and hid it in the toilet.
The same month, Bich's husband went to work, leaving medicine that his doctor prescribed him at home. Bich replaced the medicinal content inside the capsules with cyanide, and then left the drugs in their original location. She also left the house to not raise suspicion.
At noon, she saw that her husband was returning home, so she stalked him to see if he would drink the cyanide as she had planned. After watching her husband take the poison, she left the scene. Her husband died two days later. Bich told her family and neighbors that he had a stroke, before quickly cremating him.
Vendetta
After her husband died, Bich publicly dated a local unemployed man. As she did not have money at the time, Bich wanted to borrow money from her sister, but was denied as the sister did not want her to "borrow money for a lover."
Lam, Long’s father, also knew of Bich's affair, and advised her to not be in a relationship with someone without stable employment.
Bich believed that her sister and father-in-law wanted to separate her and her lover, so she planned for revenge.
When Bich’s sister and father-in-law were not home, leaving her 7-year-old niece and 12-year-old nephew at home, Bich put the cyanide into the children's drinks. They died a few days later.
At this point, the surviving family members still did not suspect any foul play. They believed that the house they were living in "had problems," so planned to fix it.
Bich and Lam's wife then encountered conflicts as they did not agree on how exactly to fix the house. So, Bich plotted revenge.
On June 22, as Long was studying alone, Bich told him that he had too much acne. She told Long that she used to have the same problem, and after drinking medicine it went away, offering to buy him the same medicine.
Long agreed to the offer. Bich then went to the local pharmacy, and asked for painkillers with capsules. She then replaced the capsule contents with cyanide and gave them to Long. After taking them, Long quickly fell unconscious, so his mother took him to a hospital in Ho Chi Minh City.
After the hospital reported that Long had cyanide poisoning, the families began to see something amiss, and reported what happened to the police. Looking at the previous deaths, they realized they all had similar symptoms: headache, nausea and vomiting.
Bich then quickly buried her cyanide can at a nearby graveyard to avoid detection.
Police officers later found Bich suspicious as she loved to gamble, had complex relationships, and frequent conflicts with her family.
Authorities later found out that following her husband’s death, Bich received VND800 million ($31,500) in insurance, and used the money to pay off debts, and for her personal spending.
When she was first summoned by her police, Bich was silent and did not admit to her crimes. Only after the police showed her numerous pieces of evidence did she confess.
"The suspect did not show signs of fear. Her face was emotionless and showed no signs of remorse," an investigator said.
An investigation is ongoing.