A year after the assassination of former Japanese Prime Minister Shinzo Abe on Saturday, the man accused of the shooting has been spending the majority of his time reading history and philosophy books while awaiting the scheduling for his trial, according to his lawyers.

While Tetsuya Yamagami seemed to be on edge immediately after the incident, the defendant has since relaxed and also reads newspapers every day at the Osaka Detention House, the lawyers said.

A police vehicle carrying Tetsuya Yamagami, the man accused of fatally shooting former Japanese Prime Minister Shinzo Abe last year, arrives at Nara Nishi Police Station in Nara, western Japan, on Jan. 10, 2023.  He was moved there from Osaka Detention House in Osaka as his psychiatric evaluation period ended the same day. (Kyodo)

"He seems to be randomly reading about things he's interested in," one of the lawyers said.

Abe, Japan's longest-serving premier, died on July 8 last year after being shot at close range with a handmade gun while giving a campaign speech in Nara Prefecture two days ahead of the House of Councillors election. Yamagami was arrested on the spot.

The 42-year-old told investigators that he had held a grudge against the Unification Church, a South Korea-based religious group known for its mass weddings and aggressive donation solicitations, after his mother's substantial financial donations caused their family to fall apart.

He targeted Abe in the belief the former prime minister had links to the group, investigative sources have said.

Yamagami has declined visitation from his mother, according to sources familiar with the matter.

He has also received letters, both sympathetic and condemning, from across the country since he was detained, the sources said. He has expressed gratitude for the supportive messages.

In January, after around six months of psychiatric evaluation by prosecutors, Yamagami was indicted for murder and violating the firearms control law.

The first pretrial proceedings at the Nara District Court on June 12, which Yamagami was scheduled to attend, were canceled after a suspicious box was delivered to the court the same day. The cardboard box was later found to have contained petitions seeking leniency for him, said the sources.

He is considering calling off his attendance at the pretrial session where court officials, prosecutors and lawyers are likely to narrow down issues, review evidence and set the trial schedule, the sources said.

While the first day of his trial is expected to come next year, the defense team said they believe it may not even happen in the first half of 2024 due to the overwhelming amount of evidence and that it is also "undecided" what he will argue in the trial.