[17] Yamagami graduated from Nara Prefectural Koriyama Senior High School in 1998, with plans of becoming a firefighter, but was unable to pass a required test due to his near-sightedness.
[24][18] Yamagami's older brother, who had a longtime struggle with lymphoma which led to him losing eyesight in one eye, was not able to afford medical treatment; he died by suicide in 2015.
Originally working in the construction contractor industry, he obtained an attorney's licence and started his own legal consulting firm in Osaka.
[30][31] Yamagami's mother often asked him for money to donate to the Unification Church while neglecting her children, to the point that he once threw a cup of tea on her in a fit of rage.
[29] For the whole year since the assassination, Yamagami refused to respond to his mother's requests for visitation in the detention centre, while he was reading and expressing appreciation to letters from his supporters.
[32] Yamagami joined the Japan Maritime Self-Defense Force (JMSDF) in August 2002; he was posted to Kure Naval Base and assigned to the destroyer JDS Matsuyuki.
[33][14][34] In February 2005, while in the military,[18] Yamagami attempted suicide in hope of his siblings receiving his life insurance payout after learning that his mother neglected his brother to attend Unification Church events in South Korea.
[37] On 8 July 2022, Tetsuya Yamagami appeared at the northern exit of Yamato-Saidaiji Station, Nara at 11:30 am, where Shinzo Abe was delivering a campaign speech for Kei Satō, a Liberal Democratic Party candidate in the upcoming Upper House election.
[43][44][45] Before any formal charges were brought against Yamagami,[46][47] he was held at the Osaka Detention House and had been psychiatrically evaluated to determine if he was mentally competent to be indicted.
[50] On 24 December 2022, the Nara District Prosecutor's Office determined that Yamagami was competent enough to stand trial on the murder charge, based on factors including the capability of making the firearm allegedly used in the assassination.
The charge related to the Public Election Law [ja] was dismissed because the prosecutors determined that there was insufficient evidence to support the allegation.
A News Post Seven [ja] journalist speculated that the prosecutors were waiting for public sentiment over the assassination to quiet down, due to the aftermath brought by the incident as well as sympathy and admiration towards Yamagami.
Shiroo was sentenced to death during the first trial in Nagasaki District Court on the grounds of "strong antisocial behavior which denies the foundation of democracy".
[66] In a letter sent to journalist Kazuhiro Yonemoto [ja] on 7 July, the day before the incident, Yamagami introduced himself as "Mada Tari-nai" (まだ足りない, lit.
[86] Yamagami posted on Twitter that he was "willing to die to liberate every person involved in the Unification Church", and that he had "no concern about what will happen to the Abe administration as a result".
[92][clarification needed] In May 2023, it was revealed that Yamagami also sent two private messages on Twitter to the anti-cult journalist Eito Suzuki nine days before the assassination.
Yamagami claimed that the messages were about him being a regular reader of Suzuki's writing, and a question about an important figure from the UC who would attend a 10 July 2022 ceremony held in Urawa-ku, Saitama.
[97][98][99] From around the time his mother went bankrupt, Yamagami wandered around the Unification Church building carrying a knife, looking for an opportunity to kill Hak Ja Han.
[105] On the day before the assassination, Yamagami travelled by Shinkansen and attended an LDP rally in Okayama Prefecture with the intent of killing Abe there; he was forced to backtrack due to entry protocols.
[115] Making homemade weapons was a costly endeavour for Yamagami, who ran out of funds very soon, could not hold down a steady job, and was several hundreds of thousands of yen in debt, which pushed him to proceed with assassinating Abe in July 2022.
[116][115] Yamagami told police that he had test-fired his homemade gun in a facility linked to the Unification Church on 7 July, the day he went to Okayama to attend Abe's election campaign and assassinate him, later giving up the plan.
[122][123] Police discovered seven homemade firearms similar to that weapon, two of them unfinished,[124] as well as possible explosive devices, during a search of his home following his arrest.
[127][128][129] Yamagami stated that he tested his improvised firearms by firing them at multiple wooden boards with an aluminium-covered tray for storing dry gunpowder that he produced from fertiliser,[130] which were later recovered from his vehicle.
[106] However, notes obtained from Yamagami's parents' home by the investigators reveal that he did not want to "cause trouble to the bystanders" and believed that an explosive may not kill Abe, so he instead began making his own gun.
Under the public pressure, the responsible ministry decided to file a dissolution order against the UC with the Tokyo District Court on 13 October 2023, after nearly a year of investigation of wrongdoings.
These cosplayers held cardboard signs displaying the leaders they were against: Abe, Ali Khamenei, Vladimir Putin and Xi Jinping.
[144] The sponsors of the petition denied the accusation from opponents that they approved of murder, but sympathised with Yamagami because his suffering as a shūkyō nisei was not an isolated case.
[148][149] The preview version of Revolution+1, a fictional-biographical film[c] based on the reports about Yamagami directed by Masao Adachi was premiered in small theatres across Japan on Abe's state funeral.
Criminologist Nobuo Komiya [ja] warned that "more people began to justify [their radical actions] when dealing with their family and religious issues", and that Yamagami being "treated and followed like a revolutionary leader was alarming".
[144] Nine months after Abe's death, an attempted assassination of Fumio Kishida occurred; commentators believed that the perpetrator was inspired by Yamagami.