Takahiro Shiraishi, the man who used Twitter to lure suicidal women to his home, where he drugged, robbed, raped and killed them before dismembering their bodies, was yesterday given the death penalty.
Police discovered nine human heads and 240 bones stored in cooler boxes in his tiny 13.5 sq m apartment on Halloween in 2017.
His home in Zama city, 90 minutes from central Tokyo, was dubbed by Japanese media as the "house of horrors".
The nine murders took place over three months from August to October in 2017.
Eight of the victims were women aged 15 to 26. The only man was an acquaintance of one of the missing women, and was killed when he came too close to discovering Shiraishi's crimes.
Shiraishi, now 30, pleaded guilty to all the charges against him during his trial, which spanned 23 hearings and centred on his degree of culpability.
His defence lawyers argued that the murders were "consensual" and should amount to the lesser charge of homicide with consent.
"None of the victims agreed to be killed. The defendant was found to be fully responsible," presiding judge Naokuni Yano said yesterday as he sentenced Shiraishi to death.
"All the murders were well planned and the modus operandi makes it one of the most malicious murders ever in the history of crime. It caused massive shock and anxiety to a society where the use of social media is commonplace."
Shiraishi, who wore black-rimmed glasses and a white mask, was stone-faced and emotionless during the 80 minutes or so it took the judge to read the entire judgment, media reports said.
Judge Yano, turning to Shiraishi after the verdict, asked if he was even listening. Shiraishi replied: "Yes, I understand."
In media interviews leading up to the verdict, he had complained that the process was taking too long and that he would gladly accept the death penalty.
During his trial, he apologised to some of the bereaved families who took the stand, though he would not meet their eyes. "I am sorry for having killed some of the victims, with whom I spent a lot of time, and would like to apologise to these families."
But he had also been defiant: "But for the others, I don't really feel a deep sense of regret. In any case, I am sorry only because I failed when I got caught. If I wasn't arrested, I will not be regretting anything."
Once a scout for the seedy sex industry in Shinjuku's Kabukicho district, Shiraishi had a flair for sweet-talking young women into doing his bidding.
Jobless in 2017, he sought out suicidal women using two Twitter accounts. In one, he posed as a suicide guru skilled at helping people end their lives. In the other, he cast himself as a forlorn man who wanted company for his misery, seeking out others with whom he could enter into suicide pacts.
To ensure his victims would not back out at the last minute, he arranged to meet them at a train station near their homes before travelling together to his apartment.
There, he fed them alcohol, tranquillisers and sleeping pills, before assaulting and raping them.
He killed his first victim, a 21-year-old woman, after she demanded the return of a loan. His subsequent victims, he said, were murdered because he feared they would report his sexual assault on them.
"There is no doubt that I sliced up the bodies in my bathroom with the intention of destroying evidence," he once told police investigators. "I disposed of their flesh and internal organs like garbage, but kept their bones out of fear that I would be caught."
Shiraishi was found out only when the brother of the final victim hacked into her Twitter account and found the disturbing messages.
The prosecutors said in closing arguments that Shiraishi's crimes "deserve death", adding: "Nine young lives were taken in such a short span of two months."
The father of one of Shiraishi's victims said in an NHK interview: "Personally, I wanted him to get a life sentence over which he has no choice but to atone for his wrongdoings, rather than give him the death penalty he wanted."