Police in the northern province of Phu Tho Thursday arrested a local man on suspicion of killing four people the day before.
Nguyen Cong Dung, who lives in Binh Bo Commune, allegedly stabbed his neighbors Cao Thi Thom, 36, and 15-year-old Ngo Van Thinh to death on Wednesday morning, police said.
He also slashed and killed another neighbor, Nguyen Cong Chinh, according to initial reports.
Chinh's wife, Han Thi Chi, suffered injuries when Dung set fire to Chinh's house and died later at the local hospital, police said.
Dung then drove away on a stolen motorbike. He was later arrested in the neighbouring province of Vinh Phuc.
Police are investigating the case.