On the morning of June 27, 2025, Japan returned to global headlines with a chilling announcement: the execution of its most notorious serial killer in recent memory—Takahiro Shiraishi, widely known as the "Twitter Killer." This marked the first execution in Japan in three years, reigniting intense public and international debates around capital punishment, mental health, and the dangers of social media.
Who Was the "Twitter Killer"?
Takahiro Shiraishi, a 34-year-old man from Zama City, Kanagawa Prefecture, shocked the nation in 2017 after confessing to the brutal murders of nine people, mostly young women. His nickname, the “Twitter Killer,” came from the fact that he used the social media platform Twitter (now X) to lure emotionally vulnerable individuals—mostly those who had expressed suicidal ideation—to his apartment under the pretense of helping them die painlessly.
Instead, Shiraishi murdered his victims, dismembered their bodies, and stored their remains in coolers and toolboxes in his small one-room apartment.
The Horrific Crimes: A Timeline
Between August and October 2017, Shiraishi targeted individuals through keywords related to suicide on Twitter. He approached them pretending to be sympathetic, claiming he would either help them die or die with them. Once they trusted him enough to meet, he lured them into his apartment and murdered them—eight women aged between 15 and 26, and one man who was a friend of one of the victims.
In a later police interview, Shiraishi admitted:
“I killed them for sexual satisfaction and money. I had no intention of helping them die.”
The sheer cruelty and deception stunned Japanese society and sparked national conversations about social media regulation and mental health support systems.
Arrest and Trial
On October 31, 2017, Japanese police discovered the horrific scene in Shiraishi’s apartment after investigating the disappearance of a 23-year-old woman. What they found—dismembered body parts from multiple victims—was described by officers as "the worst crime scene in Japan in decades."
During his trial in 2020, Shiraishi pleaded guilty to all counts. His defense attempted to argue that the murders were consensual suicides, but the court dismissed that claim after examining messages and testimonies.
In December 2020, Shiraishi was convicted on nine counts of murder, along with charges of sexual assault and body desecration. He was sentenced to death by hanging, Japan’s standard method of execution. He did not appeal the sentence.
The Execution: June 27, 2025
Shiraishi was executed by hanging, the first execution in Japan since July 2022. Japanese law allows the Minister of Justice to authorize executions, which are carried out in secret. Inmates are typically not informed of the execution date until the morning of their death, a practice that has drawn sharp criticism from human rights organizations such as Amnesty International and Human Rights Watch.
Minister of Justice Keisuke Suzuki stated that the execution was warranted due to the “selfish and extremely cruel motives” of the crimes, which “caused deep pain and irreversible loss to many families.”
Public Reaction in Japan
Public opinion in Japan generally supports capital punishment. According to a 2019 government survey, over 80% of Japanese citizens favored keeping the death penalty, particularly for heinous crimes.
Many family members of the victims expressed relief after the execution, though others noted that no punishment could ever truly bring closure.
At the same time, some Japanese citizens and activists questioned whether enough had been done to prevent such tragedies through mental health services and online safety measures. Shiraishi’s victims were individuals who had publicly expressed suicidal thoughts—yet they fell through the cracks of the system.
International Concerns About Japan’s Death Penalty
While Japan remains one of the few developed nations to retain the death penalty, it is often criticized for its secretive and psychologically harsh execution practices. Inmates can spend years—sometimes decades—on death row in solitary confinement, unaware of when they will be executed.
Organizations like the United Nations Human Rights Council and Amnesty International have long urged Japan to abolish capital punishment or at least improve transparency and due process for death row inmates.
Legacy of the Case
The “Twitter Killer” case remains a chilling reminder of how modern technology can be manipulated for unspeakable crimes. It also exposed serious gaps in Japan’s mental health infrastructure and social support systems. Since the case, Japan has begun to enforce stricter regulations on social media platforms and has increased awareness campaigns around suicide prevention.
However, critics argue that more structural changes are needed, particularly in identifying and supporting at-risk youth.