Four family members in the northern Vietnamese province of Lao Cai are suspected to have been murdered, with local authorities hunting for the prime suspect.

Tan Ta May, 22, her two-year-old and 20-day-old daughters, and six-year-old niece, were found dead near their house on Tuesday night, Colonel Dinh Tien Quan, director of the provincial Department of Police, confirmed to Tuoi Tre (Youth) newspaper on Wednesday.

According to initial reports, Tan Ong Nai, May’s husband, and his parents returned home after finishing farm work and were terrified failing to find their family members.

The main entrance and door to the kitchen were locked from the inside, Nai said, adding that he found a loaded gun there after managing to open the doors.

Police officers and several local residents began searching for the victims shortly after being notified, and found the body of Nai’s oldest daughter buried under a pile of rocks near a gully about 50 meters from their house.

May’s body was discovered in a pond, located around 100 meters from her home, with several rocks on top of her corpse.

Her newborn baby and niece were found dead and hidden in a stream 100 meters from the residence, police officers stated, adding that the family’s dog was also slashed to death.

Post-mortem examinations indicated that May was killed by a blunt force trauma to her head while the three young girls were possibly drowned.

Investigation at Nai’s house showed that the furniture was disordered and VND10 million (US$448.5) in cash had been stolen.

Over 100 police officers have been mobilized to settle the case and hunt for the potential suspects.

According to a Tuoi Tre source, investigators have identified Tan Lao Lo, 24, a resident in the victim’s neighborhood, as the prime murder suspect.

Lo was previously in a romantic relationship with May and also involved in several prior conflicts with the victim’s family.