A mother-son duo were stabbed to death at their single-storied house in Chandmarichak locality of Danapur police station area on Sunday night while in the other room, the man's wife and their two children slept peacefully.

Small time trader Ashok Kumar (45) used to sleep in his mother Manna Devi's room ever since he quarrelled with his wife Munni Devi six months ago.

The murder was discovered around 6am on Monday when Ashok's son Yash Raj (7) woke up for school and found the door to the other room open.

He entered the other room to find his father and grandmother in a pool of blood. He raised an alarm after which Munni woke up and sounded out the neighbours. The couple have a five-year-old daughter too.

"We were informed about the incident and a team reached the house to investigate," an officer at the Danapur police station said. "The main door to the house was open. The room from which the bodies were recovered was in an absolute mess, with things strewn everywhere and cupboards and suitcases open. It looked like some people had broken in to commit a robbery, killed the two and decamped with their belongings."

But the police smell a conspiracy. "It is very strange that two persons were murdered and no one in the family, including Ashok's wife, heard a thing," said an officer. "The rooms are adjacent to each other. It is very likely the two screamed when they were stabbed. Also, there must have been sounds when the room was being ransacked or when the bodies were moved from the beds to the ground. The police suspect the murder is linked to the conflict in the family. The police are also checking Ashok's background. They have come across evidence of a land dispute."

The police said a sharp weapon was used in the crime. "The woman was stabbed in the head and the man in the abdomen," the officer said. "The bodies have been sent for post-mortem and the report will give details on the time and real cause of death.

With no arrests having been made so far, Ashok's wife was also being questioned.

"She says many items from the room, including the cellphones of the dead are missing. Her own cellphone is missing. She is being questioned and the police hope to make a breakthrough soon," another officer said.