Nam Dinh police later came and seized Hung and the knives, before breaking in his house and found Hung’s parents, Do Duc Thang, 71, and Nguyen Thi Do, 62, lying dead with multiple wounds.
It is possible that Hung used methamphetamine and committed the crime under the influence, police said.
Locals said Thang was paralyzed 6 years ago in a stroke.
Hung is married and has a three year old son.They live with Hung's parents.
But the wife and the son were not at home when the crime happened.
Neighbors said Hung had some quarrels with his wife several days ago when he beat and forced her to leave the house. So she and her son moved to her parents' house.
“Sometimes, Hung worked as a bus driver assistant and has no stable job,” a neighbor said.
Pham Thi Tuyet, a neighbor, said that many people are surprised to learn about the incident because Hung is a filial son.
“He treated his parent well and I have never heard him arguing with his parents even once during more than 10 years living near their house,” she said.
By yesterday evening the police could not question Hung as the man was still under drug influence. He just said many times that he feared of “crows and snakes.”
Police are investigating the case.