Local police reported the arrest of Kazuhiro Kusakabe, the suspected driver, who allegedly admitted to intentionally ramming his vehicle into crowds to protest his opposition to the death penalty, specifically in retaliation for the execution of the aforementioned Aum cult members.

Aum Shinrikyo, which split into Aleph and Hikari no Wa in 2007, had already been formally designated a terrorist organization by several countries, including Russia,[6] Canada,[7] Japan,[8] France, Kazakhstan, as well as the European Union.

[10] The Public Security Intelligence Agency considered Aleph and Hikari no Wa to be branches of a "dangerous religion"[11] and it announced in January 2015 that they would remain under surveillance for three more years.

[12] The Tokyo District Court canceled the extension to surveillance of Hikari no Wa in 2017 following legal challenges from the group, but continued to keep Aleph under watch.

[14] The movement was founded by Shoko Asahara in his one-bedroom apartment in Tokyo's Shibuya ward in 1987, starting off as a yoga and meditation class[15] known as Oumu Shinsen no Kai (オウム神仙の会, "Aum Heavenly Sage Association") and steadily grew in the following years.

[16] Isaac Asimov's science fiction Foundation Trilogy was referenced "depicting as it does an elite group of spiritually evolved scientists forced to go underground during an age of barbarism so as to prepare themselves for the moment...when they will emerge to rebuild civilization".

[18] Lifton posited that Aum's publications used Christian and Buddhist ideas to impress what he considered to be the more shrewd and educated Japanese who were not attracted to boring, purely traditional sermons.

[20] In the early days, Aum was able to recruit a variety of people ranging from bureaucrats to personnel from the Japanese Self-Defense Forces and the Tokyo Metropolitan Police.

[21] In July 1993, cult members sprayed large amounts of liquid containing Bacillus anthracis spores from a cooling tower on the roof of Aum Shinrikyo's Tokyo headquarters.

[citation needed] At the end of 1994, the cult broke into the Hiroshima factory of Mitsubishi Heavy Industries, in an attempt to steal technical documents on military weapons such as tanks and artillery.

[31] Tadahito Hamaguchi, whom Asahara suspected was a spy, was attacked at 7:00 a.m. on 12 December 1994, on the street in Osaka by Tomomitsu Niimi and another Aum member, who sprinkled the nerve agent on his neck.

[28][32][29] On January 4, the cult tried to kill Hiroyuki Nagaoka, an important member of the Aum Victims' Society, a civil organization that protested against the sect's activities, in the same way.

[37] According to the testimony of Kenichi Hirose at the Tokyo District Court in 2000, Asahara wanted the group to be self-sufficient in manufacturing copies of the Soviet Union's main infantry weapon, the AK-74;[38] one rifle was smuggled into Japan, to be studied so that Aum could reverse engineer and mass-produce the AK-74.

[44] Police also found laboratories to manufacture drugs such as LSD, methamphetamine, and a crude form of truth serum, a safe containing millions of U.S. dollars in cash and gold, and cells, many still containing prisoners.

The media was stationed outside Aum's Tokyo headquarters on Komazawa Dori in Aoyama for months after the attack and arrests waiting for action and to get images of the cult's other members.

[citation needed] On 23 April 1995, Hideo Murai, the head of Aum's Ministry of Science, was stabbed to death outside the cult's Tokyo headquarters amidst a crowd of about 100 reporters, in front of cameras.

In June, an individual unrelated to Aum had launched a copycat attack by hijacking All Nippon Airways Flight 857, a Boeing 747 bound for Hakodate from Tokyo.

[citation needed] The reasons why a small circle of mostly senior Aum members committed atrocities and the extent of personal involvement by Asahara remain unclear, although several theories have attempted to explain these events.

Shortly after his arrest, Asahara abandoned his post as the organization's leader, and maintained silence afterward, refusing to communicate even with lawyers and family members.

At 11:50 p.m. on 31 December 2011, Makoto Hirata surrendered himself to the police and was arrested on suspicion of being involved in the 1995 abduction of Kiyoshi Kariya, a non-member who had died during an Aum kidnapping and interrogation.

[70] According to Robert Jay Lifton, an American psychiatrist and author:[Asahara] described a final conflict culminating in a nuclear 'Armageddon', borrowing the term from the Book of Revelation 16:16"[19]Humanity would end, except for the elite few who joined Aum.

[20] Kaplan notes that in his lectures, Shoko Asahara referred to the United States as "The Beast" from the Book of Revelation, predicting it would eventually attack Japan.

[73] Furthermore, Lifton believes, Asahara "interpreted the Tibetan Buddhist concept of phowa in order to claim that by killing someone contrary to the group's aims, they were preventing them from accumulating bad karma and thus saving them".

An article in the Mainichi Shimbun newspaper on 11 September 2002 showed that the Japanese public still distrusts Aleph, and compounds are usually surrounded by protest banners from local residents.

[80] In 2001, Russian Aum members had reportedly planned to attack the Tokyo Imperial Palace with explosives in an effort to free Asahara from police custody.

[81] In January 2003, Japan's Public Security Intelligence Agency received permission to extend the surveillance for another three years, as they found evidence which suggested that the group still revered Asahara.

The following day Japanese police raided the offices of Aleph in order to "prevent any illegal activities by cult members in response to the confirmation of Asahara's death sentence".

[92] The papers included photographs of PSIA employees and directors, police officers, and lawyer Taro Takimoto, who helped followers leave Aum Shinrikyo.

[80] In November 2017, Japanese police raided five offices of Aleph in an investigation into the group's recruiting practices after a woman paid tens of thousands of yen for study sessions.

[96] On 1 January 2019, in Tokyo, Aum sympathizer Kazuhiro Kusakabe told authorities he intentionally rammed into pedestrians crowded into narrow Takeshita Street in Harajuku district as a terrorist attack in "retaliation for an execution".