The decomposed body of a 71-year-old man was found in his apartment in Borivli (West) after neighbours complained of foul smell.
The police suspect that the deceased, Subash Desai, was murdered as his throat had been slit and there was a deep injury on his head.
"It appears that Desai had been murdered either on Saturday night or Sunday morning because the body was badly decomposed," said an officer from the Borivli police station, requesting anonymity.
The incident came to light on Monday morning, when neighbours informed the police control room about foul stench emanating from Desai's second-floor flat at Krishna Nagar building on Chandavarkar Road. They broke open the door and found his body in the living room.
Desai lived alone, while his wife Chhaya and son Anand, a stockbroker, live in Shimpoli because they did not get along.
His daughter, Sonika, is married and lives in Andheri.
While the police were inspecting Desai's flat, Satya, the son of Desai's former domestic help, too reached there.
Satya, who studies in class 12, frequently visited Desai because he used to fund his education. The police are questioning him.
The neighbours told the police that they had last seen Desai on Saturday evening. He had also visited his elder brother's widow in Shimpoli the same morning.
"The family used to live at Sri Nagar Society located opposite the building. As the society is undergoing redevelopment, Desai shifted here three years ago, while the other family members had moved to Shimpoli," said a relative, who did not wish to be identified.
The police have sent the body to Bhagwati Hospital for a post-mortem.