POLICE found nine dismembered corpses, including two severed heads, at an apartment near Tokyo.
The authorities were initially led to Shiraishi's apartment while searching for a missing 23-year-old Tokyo woman who had posted on Twitter that she was "looking for someone who will die with me".
Shiraishi was arrested on Tuesday after finding the bodies of eight females and one male in cold-storage cases, covered with cat litter and hidden in his apartment in Zama, a city southwest of the capital. Police found the bodies of seven other women and one man in the apartment. Three days later, the older brother of the woman lodged a missing persons report with the Takao Police Station.
According to Jiji Press (wire service in japan), police found the two heads inside a cool box at the entrance of the apartment before being shocked about the rest of the bodies.
Shiraishi threw out some of the body parts as rubbish, along with the victims' belongings, reports said.
According to The Asahi Shimbun, the brother provided the police with Shiraishi's Twitter handle, and investigators identified another woman who had been in touch with the suspect.
Police have said Shiraishi confessed he tried to hide evidence.
The official did not give his name, in line with police policy.
Her brother contacted the police on October 24, saying she had been missing since October 21.
The case captured attention in a country known for public safety, topping news with reports that showed the building where the suspect lived in a small studio apartment.
"I thought it smelled like sewage", the neighbor said.
The woman had met Shiraishi after posting on a suicide website that she wanted to kill herself. "It was something I never smelled before".
Earlier this month, a man was arrested for killing his wife and five children after setting fire to their house.
In Japan, a low-crime country, it is the grimmest such case since a former employee of a centre for the disabled went on a knife rampage there, killing 19 people a year ago.