Naogaon: A man was allegedly stabbed to death by his younger son while the son was killed by his elder brother at Shimulia village in Sadar upazila of Naogaon on Thursday night.

The deceased is Tajim Uddin Sardar, in his seventies, and his younger son Ashraful Islam of the village.

Tajim Uddin’s two sons—Baitul Sardar and Ashraful Islam—were mentally ill, said officer-in-charge of Sadar Police Station Tariqul Islam quoting the family members.

On Thursday night, Baitul, elder brother of Ashraful, kept him confined to a room where Tajim Uddin was sleeping at about 11:30pm.

At one stage, Ashraful hit his father Tajim Uddin with a sharp weapon, leaving him dead on the spot.

Hearing screams, Baitul opened the door and found his father dead. Angered by the incident, Baitul hit Ashraful with a stone grinder on his head, leaving him unconscious.

Later, he was taken to Sadar hospital where the doctors declared him dead.

A case was filed in this connection.