Segundo o autor o motivo não foi político mas sim pessoal:
>After his arrest, Yamagami told investigators that he had intended to kill Abe for personal reasons, with no political motive.[68][69][70][71] He had stalked him in various locations, including when Abe gave a campaign speech in Okayama Prefecture the day before the assassination.[72][73] He also said he held a grudge against a religious movement, the Unification Church,[74] which he believed was connected to Abe.[71][75][76] Yamagami said that his mother, a former member, had gone bankrupt after making large donations to the church,[77][67] and that he held Abe responsible for spreading the movement to Japan.[78][79] According to The Asahi Shimbun, Yamagami's mother filed for bankruptcy at the Nara District Court in 2002.[67] Yamagami had been researching the relationship between the church and Abe in the months before the attack.[80] He stated that he first planned to assassinate a high-ranking official of the church,[81] but later switched his target to Abe.[82][83] Police initially refused to elaborate on the religious group,[84][85] but it was later revealed to be the Unification Church.[86] Yamagami told police that he kept track of Abe's schedule during his visit to Nara City via Abe's website.[76] He also claimed that he was planning an attack for "several months" and had built the weapon used in the shooting.[87][88]