TOKYO >> Japanese authorities have obtained court approval to extend the detention of the suspect in former Prime Minister Shinzo Abe’s assassination earlier this month for 10 more days until they file formal charges.

Abe, one of Japan’s most influential politicians, was assassinated on July 8 in the western city of Nara, shocking a nation known for safety and strict gun control.

The alleged assassin, Tetsuya Yamagami, 41, was arrested immediately after the shooting and has been held for questioning. He can be detained until July 29, when prosecutors must decide whether to formally press murder charges.

Nara prefectural police have said Yamagami, who had served in the Japanese navy in the early 2000s, told investigators that he killed Abe because of rumored links between the former prime minister and a religious group that he hated. Yamagami reportedly was distressed because his mother’s massive donations to the Unification Church bankrupted the family.

Over the weekend, police obtained a letter they believe Yamagami had mailed to a journalist the day before the attack, describing how his mother’s overspending destroyed and bankrupted his family because of her devotion to the church. He said the experience “distorted my entire life.”

In the typed, one-page letter, the suspect allegedly said Abe was not his essential target even though he felt bitter toward him. He said that Abe was just one of the “sympathizers” of the church and that it would be impossible to kill all members of the church’s founding family — hinting at his decision to target Abe instead.

Yamagami allegedly said in the letter that he no longer had capacity to think about political consequences Abe’s death may cause.

Police have said the suspect had test-fired his powerful handmade guns at least twice — in the mountains and targeting a local branch of the Unification Church.

On Tuesday, Ryo Sakai, head of the Maritime Self Defense Force, told reporters that his troops were fully cooperating with police investigations. Yamagami, who was assigned to a destroyer based at Hiroshima, likely acquired more knowledge of firearms than ordinary citizens, even though navy training does not involve handmade guns.

Prime Minister Fumio Kishida has asked members of the governing party to be united to overcome difficulties amid a growing speculation of a power struggle among members of Abe’s party wing — the largest among the Liberal Democrats — over who should lead the faction.

Senior LDP lawmakers on Tuesday called for members to prepare for a state funeral for Abe. A smaller funeral at a Tokyo Buddhist temple was held last Tuesday and Abe was cremated, but Kishida announced plans for a state funeral in the fall in an event that will also serve as a diplomatic gathering. Abe’s death has prompted condolences from representatives of more than 100 countries.

The plan for the state funeral for a leader whose arch-conservative ideology has divided public opinion has triggered mixed reaction from opposition groups.