Investigative sources say Japanese prosecutors have decided to indict the suspect in the shooting death of former Prime Minister Abe Shinzo, based on the results of psychiatric evaluation.

Public prosecutors in Nara, western Japan, sent Yamagami Tetsuya to a detention house to determine whether he can be held criminally responsible, following his arrest in July.

The evaluation was conducted by interviewing the suspect about his family environment, his relationship with his mother and other matters.

Investigative sources say the prosecutors also determined that Yamagami is mentally fit to be tried, as he built handmade guns and carefully prepared for the attack by checking Abe's campaign schedule.

The period of the suspect's detention for mental evaluation will expire on January 10, and the prosecutors are expected to indict him by January 13, when his period of detention ends.

Yamagami fatally shot the former prime minister on July 8 during an election campaign speech in Nara.

The suspect reportedly told police that he was motivated by a grudge against the religious group widely known as the Unification Church.

He says he shot Abe because he believed the former prime minister had close ties with the group.

He also claimed his mother's huge donations to the group left his family in financial ruin.