A man in the southern province of Dong Nai set fire to his house on Sunday killing his wife and daughter.
Nguyen Van Hay, 35, had argued with his wife beforehand. So he had bought the petrol some time ago and had hidden it at home for the purpose of killing her, local news website VietNamNet reported the police as saying Monday.
It's not available when he bought the petrol.
His daughter is 14. She was killed, along with her mother, while she was sleeping. The house took 15 minutes to burn down.
Police have detained Hay for further investigation.