TOKYO — A man convicted of murder for killing and dismembering nine people in his apartment near Tokyo was executed Friday, Japan’s Justice Ministry said.

Takahiro Shiraishi, known as the “Twitter killer,” was sentenced to death in 2020 for the killings in 2017 of the nine victims, most of whom had posted suicidal thoughts on social media. He was also convicted of sexually abusing female victims.

Police arrested him later that year after finding the bodies of eight teenage girls and women as well as one man in cold-storage cases in his apartment.

Investigators said Shiraishi approached the victims via Twitter, offering to assist them with their suicidal wishes. He killed the three teenage girls and five women after raping them. He also killed the boyfriend of one of the women to silence him.

“The case caused extremely serious outcomes and dealt a major shockwave and unease to the society,” Justice Minister Keisuke Suzuki told an emergency news conference. He said he signed the execution earlier this week, but did not witness Shiraishi’s hanging.

The execution was carried out as calls grow to abolish capital punishment or increase transparency in Japan after the acquittal of the world’s longest-serving death row inmate Iwao Hakamada last year.

Suzuki justified the need for the execution in Japan, noting a recent government survey shows an overwhelming majority of the public still supports capital punishment, though opposition has somewhat increased.

“I believe it is not appropriate to abolish execution,” Suzuki said, adding there is growing concern about serious crime.

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Shiraishi was hanged at the Tokyo Detention House in secrecy with nothing disclosed until the execution was done.

Japan now has 105 people on death row, including 49 seeking retrials, Suzuki said.

Executions are carried out in secrecy in Japan, where prisoners are not even informed of their fate until the morning of their hanging.

Since 2007, Japan has begun disclosing the names of those executed and some details of their crimes, but disclosures are still limited.

Japan and the U.S. are the only two countries in the Group of Seven leading industrialized nations that retain capital punishment.

Japan’s most recent execution, in July 2022, was of a man who killed seven people in a vehicle crash and stabbing rampage in a crowded Tokyo shopping district of Akihabara in 2018.

Japan’s crime rate is relatively low, but it has seen some high-profile mass killings in recent years.