Ho Chi Minh City police are questioning the parents of a toddler who died of respiratory decline brought on by poisoning on Wednesday .
Doctor Pham Van Quang, deputy head of the emergency care department at Children’s Hospital No.1, said Huynh Quoc Em, 2, died at around noon of pulmonary fibrosis.
His 7-year-old brother Huynh Van Quoc, who has survived, was admitted with the same symptoms, only milder.
Quang said they will have to closely monitor his condition for several more weeks.
Quoc hasn't required a respirator and has been able to eat porridge spoon-fed to him by his father.
A major hospital in the Mekong Delta province of An Giang treated the boys for a week before sending them to the HCMC hospital on November 22, with a diagnosis of acute liver inflammation.
Their respiratory systems declined several days later.
Tests at the city’s forensic lab found traces of herbicide in their blood and urine.
Doctors also found ulcerated injection marks on their buttocks and shoulders, and they suspected that someone deliberately poisoned the boys.
They have sent blood samples to various labs for further analysis.
Huynh Quoc Bao, the father from An Giang, told Tuoi Tre (Youth) newspaper he beat his wife of eight years, Nguyen Thi Be Dao, after an argument.
Following the beating, she took the boys to her family in Ba Ria-Vung Tau Province, just outside HCMC.
Her family recently informed him that his children were sick and urged him to take them to hospital.
He said he found bruises on their bodies upon receiving them.
“I didn't know what had happened. Now I just hope the doctors can save them.”
A Tuoi Tre reporter met with the mother Dao, 25, at a hospital in Ba Ria-Vung Tau on Tuesday night where doctors were administering fluids to her, intravenously.
Dao said she once hit her eldest son on the head with a cane because he refused to study.
She said she never injected them with anything.
The mother is being questioned for her possible role in the incident, which closely resembles a number of cases in Vietnam in which parents tried to kill themselves and their children following a family crisis.
Ba Ria-Vung Tau police say they'll press ahead with their investigation.