Former Japanese Prime Minister Shinzo Abe's assassination resulted from an extremely rare act of gun violence in the country.

Caption

Former Japanese Prime Minister Shinzo Abe's assassination resulted from an extremely rare act of gun violence in the country. / AP

Former Japanese Prime Minister Shinzo Abe's assassination resulted from an extremely rare act of gun violence in the country.

Caption

Former Japanese Prime Minister Shinzo Abe's assassination resulted from an extremely rare act of gun violence in the country. / AP

A day after his assassination shocked the world, police investigators are trying to learn the motives behind the killing of Japan's former Prime Minister Shinzo Abe. Although the shooter denied political motivations, he told police the attack had been planned for months.

Abe was shot from behind in the western city of Nara while speaking at a campaign event ahead of Sunday's parliamentary elections.

Police arrested Tetsuya Yamagami, 41, at the scene. Yamagami, an unemployed former sailor in Japan's maritime armed forces, confessed to the assassination in which he used a handmade firearm, according to police.

Police said Yamagami told them that he went to Okayama, another western city, where Abe was giving another campaign speech the day before the shooting, according to Kyodo News, which cited "investigative sources."

Yamagami denied any political motivations for the assassination, according to police.

Yamagami mentioned his mother's bankruptcy after she donated to an unnamed religious organization with which Abe had alleged ties, according to Japanese media reports.

Friday's shooting happened in a country where gun violence and political attacks rarely occur. Police searched Yamagami's home and found other improvised weapons, including handmade explosives, NPR's Anthony Kuhn reports.

Anyone who has even a limited knowledge of how guns work could have made the weapon used in the attack, firearms commentator Tetsuya Tsuda told Reuters. Tsuda said the weapon could have been made in less than half a day.

Tomoaki Onizuka, Nara's head of prefectural police, admitted there were problems in security and apologized for failing to prevent the attack, according to reports from Kyodo News.

Japan has some of the lowest rates of gun ownership and gun violence in the world, with only one person killed by gun violence in 2021, according to the country's National Police Agency.

The Gun Violence Archive recorded over 45,000 firearm deaths in the U.S. that same year.

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