Kepada investigator, Yamagamai menyatakan bahwa motif pembunuhan adalah bukan mengenai politik melainkan alasan pribadi.<ref>{{cite news |date=8 July 2022 |title=Police: Suspect 'intended to kill' former PM Abe |url=https://www3.nhk.or.jp/nhkworld/en/news/20220708_37/ |work=[[NHK]] |agency=[[NHK]] |accessdate=8 July 2022 |url-status=live |archive-date=8 July 2022 |archive-url=https://web.archive.org/web/20220708070233/https://www3.nhk.or.jp/nhkworld/en/news/20220708_37/ }}</ref><ref name="bbc2">{{cite news|url=https://www.bbc.com/news/world-asia-62089486|title=Shinzo Abe: Explosives found at shooting suspect's home – reports|date=8 July 2022 |publisher=BBC news|access-date=8 July 2022|archive-date=8 July 2022|archive-url=https://web.archive.org/web/20220708040554/https://www.bbc.com/news/world-asia-62089486|url-status=live}}</ref><ref>{{Cite web |date=9 July 2022 |title= |script-title=ja:安倍元首相、銃撃され死亡 ６７歳、選挙応援演説中―元海自隊員の４１歳男逮捕、「特定の団体に恨み」・奈良：時事ドットコム |trans-title=Former Prime Minister Abe, shot dead 67 years old, in an election support speech-A 41-year-old man of a former sea self-member was arrested, "a grudge against a specific group" Nara: Current affairs dot com |url=https://www.jiji.com/jc/article?k=2022070800546&g=pol |url-status=live |archive-url=https://web.archive.org/web/20220709005940/https://www.jiji.com/jc/article?k=2022070800546&g=pol |archive-date=9 July 2022 |access-date=9 July 2022 |website=時事ドットコム (JIJI PRESS) |language=ja}}</ref><ref name="fnn_interrogation">{{cite news |date=8 July 2022 |title= |script-title=ja:安倍元首相銃撃で山上容疑者「ある特定の宗教団体に恨み」 |language=ja-JP |trans-title=Former Prime Minister Abe shoots Yamagami "grudge against a specific religious group" |work=FNNプライムオンライン |url=https://nordot.app/918118217387769856 |url-status=live |access-date=8 July 2022 |archive-url=https://web.archive.org/web/20220708141109/https://nordot.app/918118217387769856 |archive-date=8 July 2022}}</ref> Ibunya mengalami kebangkrutan setelah memberikan donasi yang besar pada [[T’ongil-gyo|Unifikasi Gereja Unifikasi]] pada 2002,<ref name=":4">{{Cite web |date=9 July 2022 |script-title=ja:父は急死、母は宗教団体へ多額の金 安倍氏銃撃容疑者の生い立ち：朝日新聞デジタル |trans-title= Father died suddenly, mother went to a religious group A large amount of money Mr. Abe's background of the shooting suspect |url= https://www.asahi.com/articles/ASQ796KGPQ79PTIL02M.html?iref=ogimage_rek |url-access=subscription |url-status=live |archive-url= https://web.archive.org/web/20220709213311/https://www.asahi.com/articles/ASQ796KGPQ79PTIL02M.html?iref=ogimage_rek |archive-date= 9 July 2022 |access-date=9 July 2022 |website=朝日新聞デジタル (Asahi Shimbun) |language=ja}}</ref><ref name=":5">{{Cite web |title=「山上容疑者の母は会員」「献金額たどれず」 旧統一教会が会見：朝日新聞デジタル |url=https://www.asahi.com/articles/ASQ7C66DTQ7CUTIL03S.html?iref=ogimage_rek |url-access=subscription |access-date=2022-07-11 |website=朝日新聞デジタル (Asahi Shimbun) |language=ja |archive-date=12 July 2022 |archive-url=https://web.archive.org/web/20220712023326/https://www.asahi.com/articles/ASQ7C66DTQ7CUTIL03S.html?iref=ogimage_rek |url-status=live }}</ref> dimana ibunya adalah anggota organisasi tersebut,<ref>{{cite web |date=10 July 2022 |script-title=ja:安倍元首相銃撃の山上容疑者 優等生バスケ少年を変えた"統一教会で家庭崩壊"…事件前には近隣トラブルで絶叫【原点写真入手】 |trans-title=Former Prime Minister Abe's shooting Yamagami suspected "House collapse at the unified church" that changed the honor student basketball boy… Screaming due to neighborhood trouble before the incident [Origin photo obtained] | lang = ja |url= https://news.yahoo.co.jp/articles/7516906241ff0df152c139cc31ed99d970987951 |url-status=live |archive-url= https://web.archive.org/web/20220710022439/https://news.yahoo.co.jp/articles/7516906241ff0df152c139cc31ed99d970987951 |archive-date=10 July 2022 |access-date=10 July 2022 |website= Yahoo! News Japan |quote=しかしその日は、『自分の家族が統一教会に関わっていて、霊感商法トラブルでバラバラになってしまった...』と語りはじめたのです。山上さんは続けて、『統一教会は、安倍と関わりが深い。だから、警察も捜査ができないんだ』 |trans-quote= On that day, he said, "My family was involved with the Unification Church…" Yamagami continued, "The Unification Church is deeply involved with Abe, and that's why the police can't investigate".}}</ref> Yamagami geram dengan organisasi itu.<ref>{{cite web |date=9 July 2022 |title= |script-title=ja:銃撃容疑者「母親が宗教にのめり込み破産」 安倍氏に一方的恨みか |trans-title= Shooting suspect "Mother is absorbed in religion and goes bankrupt" Is it a one-sided grudge against Mr. Abe? |url=https://mainichi.jp/articles/20220709/k00/00m/040/068000c |archive-url=https://web.archive.org/web/20220709043441/https://mainichi.jp/articles/20220709/k00/00m/040/068000c |archive-date=9 July 2022 |access-date=9 July 2022 | work = [[Mainichi shimbun]] |language=ja}}</ref><ref>{{cite web |date= 9 July 2022 |script-title= ja:当初の狙いは宗教団体の幹部襲撃か「母親がのめり込み恨みがあった」 安倍元首相銃撃事件の容疑者が供述 |trans-title=The original aim was to attack an executive of a religious group or "the mother had a grudge against her." |url= https://www.yomiuri.co.jp/national/20220708-OYT1T50270/ |archive-url= https://web.archive.org/web/20220709044516/https://www.tokyo-np.co.jp/article/188540 |archive-date= 9 July 2022 |access-date=9 July 2022 | work =[[Yomiuri shimbun]] |language= ja}}</ref> Ibu Yamagami bergabung Unifikasi Gereja pada tahun 1998, dan pada tahun 1999 dia menjual tanah yang didapatkan dari warisan ayah dari ibunya dan rumah yang ditinggali bersama 3 anaknya, berkontribusi sebesar 100 juta yen (10 miliar 800 juta rupiah) kepada organisasi tersebut dan mengalami kebangkrutan setelahnya.<ref>{{cite web|url=https://www.yomiuri.co.jp/national/20220713-OYT1T50136/|archive-url=https://web.archive.org/web/20220713085752/https://www.yomiuri.co.jp/national/20220713-OYT1T50136/|script-title=ja:関係者「母親は旧統一教会に献金１億円」、土地・自宅売却で破産|language=ja|publisher=[[Yomiuri shimbun]]|date=13 July 2022|archive-date=13 July 2022|access-date=13 July 2022}}</ref> Yamagami kemudian menyelidiki keterkaitan organisasi tersebut dengan [[Shinzō Abe]] beberapa bulan sebelum penyerangan dan meyakini bahwa Shinzo menyebarkan pengaruh organisasi itu di Jepang.<ref>{{Cite web |date=9 July 2022 |script-title=ja:【速報】"特定の宗教団体"は母親と関係 「のめり込み破産」新たな供述 |trans-title=[Breaking news] "Specific religious group" has a relationship with mother "Devotion bankruptcy" new statement |url= https://www.fnn.jp/articles/-/386915 |url-status=live |archive-url= https://web.archive.org/web/20220709094309/https://www.fnn.jp/articles/-/386915 |archive-date=9 July 2022 |access-date=9 July 2022 |website=FNNプライムオンライン}}</ref> Yamagami diduga memutuskan untuk membunuh Abe setelah dia menemukan sebuah situs dimana Abe mengirimkan pesan berupa video kepada grup yang terafiliasi dengan Unifikasi Gereja.<ref>{{cite web|url=https://news.tv-asahi.co.jp/news_society/articles/000261223.html|archive-url=https://web.archive.org/web/20220711164704/https://news.tv-asahi.co.jp/news_society/articles/000261223.html|script-title=ja:動機は？旧統一教会「家庭の破綻は把握」山上容疑者「安倍総理のビデオレター見た」|language=ja|publisher=TV asahi|date=11 July 2022|archive-date=10 July 2022}}</ref>
