Police made the grisly find in the apartment in Zama, a city just outside Tokyo, after investigating the disappearance of a 23-year-old woman who went missing earlier this month. The woman had been seen walking with the man near the apartment on security camera footage, multiple media sites reported.
A number of coolers were found in the house, each containing body parts, and led to the arrest of 27-year-old Takahiro Shiraishi on suspicion of abandoning a body. Police are investigating further, reports said, the Guardian reported.
According to Jiji Press, police found the two heads inside a cool box at the entrance of the apartment on Monday before making the grisly discovery of the other bodies inside on Tuesday.
Jiji Press said police found a saw in one room. The bodies were of eight women and one man, several media reported.
A spokesman for the National Police Agency declined to confirm the reports, saying nothing had been officially announced.
Television pictures showed a heavy police presence blocking off a white-tiled terraced apartment.