Takahiro Shiraishi

was a Japanese serial killer and sex offender. He was also known as the Twitter Killer or the Zama Suicide Pact Killer, which he was labeled as in most media reports at the time of his sentencing. In Zama, Kanagawa, between August and October 2017, he murdered nine people, eight of them being young women, including three high-school girls, in an incident known as the Zama Nine Murders.

Background Shiraishi was born in Tokyo on 9 October 1990. He worked as a scout who lured women into brothels to work in the sex industry in Kabukichō, Tokyo's biggest red-light district. People warned locals about him, describing him as a "creepy scout". Shiraishi moved to an apartment in Zama in August 2017.

On the social media platform Twitter, Shiraishi invited suicidal people to his home, where he offered to either help them die or watch them kill themselves. A friend indicated that Shiraishi had played choking games with schoolfriends, and signs of his later victims indicated that they had been strangled. A woman known only as "Yumi" assisted him by contacting Shiraishi and setting up a fake appointment. They both involved the police.

The police arrived at the apartment and asked where the missing woman was. Shiraishi indicated she was in the freezer, and police found nine dismembered bodies in the house. In three cooler boxes and five large storage boxes, police found heads, legs, and arms. Neighbors corroborated the events by confirming that foul smells of rotting flesh had come from the house. Shiraishi had discarded elements of the people into his bin, which had been taken away in the recycled garbage. The nine victims were eight women and one man, all of whom were between the ages of 15 and 26.

The police investigation confirmed the missing woman had been walking with Shiraishi on 23 October 2017. Shiraishi confessed to killing and dismembering the nine people. Most of the victims were suicidal women whom he had lured on social media – in some cases, offering to help them die, and in others, proposing to commit suicide together with them.

Trial and execution Shiraishi's lawyers had intended to base their defence on the fact that Shiraishi had obtained the consent of most of his victims to kill them. On 15 December 2020, he was sentenced to death. He indicated he would not appeal his sentence. Shiraishi's death sentence was finalized in January 2021, and he was executed by hanging on 27 June 2025.