Burdwan: Three family members were found dead in their homes in Purba District Bardhaman West Bengal on Sundays, police said.
The incident occurred in Khandra Village in the Manteshwar police station area, they said.
Malabika Chakraborty (50), a widow, lived with his brother Utpal Chatterjee (45) and Son Kaushik (22) at the house, police said.
While the bodies of Malabika and Kaushik were found lying in their room, Utpal was found hanging from the ceiling fan in his room, they said.
The bodies were found after the police went home because neighbors were suspicious when they did not wake up in the morning.
Neighbors suspect that Utpal, who mentally challenged, first killed his sister and his son, and then hanged himself.
Investigation of this incident was underway, the supervisor of the Secretary of the National Police Secretary of Police said.