But once he had lured the women to his apartment, he strangled them, sexually assaulted and robbed some of them, and cut up their corpses.
He was arrested in 2017 after body parts were found in his home. The case prompted Twitter to introduce rules against promoting or encouraging suicide and social harm on its service and led Japan’s government to expand telephone and online support for people contemplating suicide.
Shiraishi told police he had tweeted about suicide and exchanged messages with several women, coaxing them to his apartment, Japanese media reported. Eight of his victims were female, including girls aged 15 and 17.
His first victim was a 21-year-old woman, whom he had met in a park along with her male acquaintance. She ended up helping Shiraishi rent an apartment in Zama, southwest of Tokyo, and transferred about $4,500 to his bank account, Japanese media reported.
Shiraishi admitted that he strangled her to avoid paying her back and later killed her male friend when he confronted him about the woman’s disappearance.
He said he had never been interested in suicide but had used it as a way to lure more victims. He found people who had tweeted under a hashtag meaning “I want to die.”
“It was easier for me to convince people with worries and other issues and manipulate them to my way of thinking,” Shiraishi said during the trial, according to media reports.
Police tracked him down after the brother of one of his victims found messages from Shiraishi in her Twitter account and informed the police. The police found body parts in cooler boxes and other containers in his apartment.
Lawyers for Shiraishi — whom Japan’s English-language media branded the “Twitter killer” — argued that he deserved a lesser charge of “murder with consent” because the women had willingly gone to his apartment seeking death.
But Shiraishi acknowledged in court, as well as to police and journalists, that none of the women had consented to die, admitting he had killed one woman while she was sleeping and murdered another shortly after she had talked of wanting to eat “something delicious” and visit a game parlor.
He was convicted of nine counts of murder, as well as robbery and forced sexual intercourse. Before his sentence, he said he was afraid of the death penalty but, given the cruelty of his crimes, expected it.
Presiding Judge Naokuni Yano said the case had caused huge “shock and anxiety” to the nation. “It is extremely grave that the lives of nine young people were taken away,” he added. “The dignity of the victims was trampled upon.”
Japan usually reserves the death penalty for those convicted of multiple murders. Executions are carried out by hanging.
In an interview with NHK in 2017, Twitter CEO Jack Dorsey called the case “extremely sad” and said the social media company needed to make sure its site “is being used in positive and healthy ways.”
Japan has the highest rate of suicide among the Group of Seven industrialized nations — just ahead of the United States. The number of suicides had fallen sharply in the past decade but shot back up this year, especially among young women, which experts believe to be linked to the coronavirus pandemic.
Despite expanded support in recent years, suicide hotlines in Japan are often overwhelmed with calls.
Jiro Ito, the head of OVA, a nonprofit trying to prevent suicide, said the case showed that vulnerable people sometimes seek help by tweeting suicidal thoughts.
“The fundamental issue reflected in this case is that there are people who cannot say ‘please help’ in person, in the real world,” he said. “That’s because they feel so lonely or too much in pain to do that. That has driven them to type on the net.”
In the United States, the National Suicide Prevention Lifeline can be reached at 1-800-273-8255 or over chat. In Japan, the Health Ministry website has contacts for people to find support by phone or online.