Partha De, 44, had reportedly stored his sister’s remains in his flat for at least six months often sleeping with the body in his bed.
It is believed the Indian man sealed the doors and windows in his flat to help mask the smell of the corpses exiting the property.
Police believe both of his dogs died last year.
Officers made the discovery as they came to the De’s flat in Kolkata, India to see to the body of his 77-year-old father, who had died earlier this week.
On removing the corpse, teary-eyed De crumbled and admitted that there were more bodies to remove.
A spokesperson for Kolkata Police said: “When we arrived at the apartment, he broke down and cried when we first approached him.
“He kept blaming everyone, including one of his uncles, for the deaths in their family he said he was living in hell.”
The B-tech engineer then tried to convince police that his sister would come back for dinner again in the near future.
An officer revealed: “Breakfast, lunch and dinner were served to his sister, including occasional snacks; it seemed he took regular care of the skeleton.
“He changed the bed sheets every day – the room was cleaned too.”
It emerged that his 47-year-old sister was a teacher and was fond of her two dogs.
While his father, Arabinda, had retired as a director of a multi-national company before setting himself on fire in the bathroom last week.
Police confirmed both deaths were unnatural.
De has since been taken to a mental hospital with psychiatrists suggesting the deaths may have triggered a mental state of delusion.