Tetsuya Yamagami, 41, has also admitted that he intended to kill Abe, believing he had ties with the group, the sources said.

Abe, Japan's longest-serving prime minister, was pronounced dead Friday, around five hours after being shot from behind during a stump speech near a train station in the western city of Nara. Yamagami was arrested at the scene, where he was wielding a homemade gun.

Yamagami told the police that the day before the deadly shooting, he went to the western city of Okayama, where Abe had also been giving a campaign speech for Sunday's House of Councillors election, according to the sources.

Lawmakers and voters have also criticised the shooting of Abe as shaking the foundation of democracy and exposing flaws in the security of dignitaries.

At a press conference, Tomoaki Onizuka, head of the Nara prefectural police, apologised for failing to prevent the incident and admitted, "It is undeniable that there were problems in the security."

Abe died from blood loss, the police said, with an autopsy determining that there were two gunshot wounds on his upper left arm and neck. There was another neck wound, but it is unknown how that was caused, they said.

Yamagami has denied he committed the crime because he was opposed to Abe's political beliefs, according to the police.

The police searched his home Friday, finding items believed to be explosives and homemade guns, including ones similar to the weapon used in the attack, they said.

Yamagami, who was unemployed, had previously worked for a manufacturer in the Kansai region from around the fall of 2020, but he quit in May this year, according to a staffing agency employee. He was previously a member of the Maritime Self-Defense Force for about three years through August 2005.

Amid punishing heat and spurts of heavy rain, nearly 500 people at one point had lined up at a spot in Nara close to the scene of the attack to pay their respects, with mourners leaving flowers, drinks and other items.

Among them was Shihori Kimura, a 17-year-old high schooler from Kyoto, also in western Japan. "For me, Mr. Abe is who I think of when someone mentions the prime minister. I wanted to thank him for his work over such a long time. Political expression must not be stopped by violence," she said.

In the afternoon in Tokyo, a car carrying Abe's body arrived at his home. His wife Akie accompanied her late husband's body in the car ride from Nara.

As the car slowly pulled in, Akie Abe bowed to the more than 100 members of the press thronged outside the residence. Following Prime Minister Fumio Kishida's visit to express his condolences, numerous LDP lawmakers came to pay their respects.

Hisashi Hieda, chairman of media firm Fujisankei Communications Group, told reporters Abe's expression looked as he always did, although his head was wrapped with bandages. Hieda joined LDP policy chief Sanae Takaichi and others to meet the car carrying the former prime minister home.

Earlier Saturday, Kishida had a telephone conversation with United States President Joe Biden, who expressed his condolences.

Biden noted the "unwavering confidence in the strength of Japan's democracy," and the two leaders also discussed how Abe's legacy would live on as the two countries continue the important task of defending peace and democracy, according to the White House.

Kishida told reporters after the phone talks that he had conveyed to Biden Japan's willingness to "protect democracy without yielding to violence."