A 48-year-old Tokyo man has been arrested on suspicion of abandoning a dismembered body in an apartment in a central Japan city, with investigative sources saying Friday the body was found cut into seven pieces.

Sources said Kazuo Sato said "I killed my brother," after he was arrested Thursday in connection to the death of a man whose body, including the severed head, was found Monday inside a closet in an apartment in Kashiwazaki, Niigata Prefecture.

Sato is suspected of hiding and abandoning the body inside the apartment sometime between March 2018, when he first started renting the room, and Monday, police said.

An autopsy showed the body to be that of a man in his 40s to 60s who died at least half a year ago, with the police saying the man is believed to be one of Sato's two brothers.

On Thursday, Sato turned himself in to police in Tokyo's Toshima district.