Tetsuya Yamagami, the man who shot dead former Japanese Prime Minister Shinzo Abe, addressed a letter to a critic of the religious group the Unification Church of Sun Myung Moon, signaling his intentions, Japanese media said on Sunday, citing the recipient.

The letter was intended for a guy who ran a site attacking the Unification Church, which Abe was associated with, according to the shooter. The letter was apparently discovered on Wednesday, five days after the former prime leader was assassinated, according to Kyodo news and the Japanese newspaper Yomiuri Shimbun.

The postmark on the envelope indicates that it was mailed on July 7, one day before the event, from Okayama Prefecture, where Abe was giving a campaign speech. Yamagami allegedly planned to shoot Abe there but changed his mind since he needed to register for the event and input his personal information.

Read next: Man who killed Shinzo Abe tried to make bomb, owned multiple guns

"I realize that this is deplorable, but Abe is not the original enemy. He is only one of the most influential sympathizers of the Unification Church," the printed letter said, as quoted by the media.  

Yamagami purportedly detailed his past in the letter, as well as the story of his mother, who allegedly joined the Unification Church and went bankrupt, wrecking the family, after paying substantial sums to the church. It was originally reported that the donations from the sale of land and property were approximately 100 million yen ($720,000 today, approximately $1,000,000 at the time).

"As much as I would like to kill them all [the leadership of the Church], I understand that it is impossible," the full letter, which was leaked to the internet, said.  Yamagami also allegedly wrote that he "can no longer contemplate what consequences, including political ones, Abe's death will have."

On July 8, Abe was attacked at a campaign in the Japanese city of Nara. Yamagami, 41, approached the lawmaker from behind and fired two rounds from around ten meters away (33 feet). According to police, Abe was aware immediately after being shot, but his health deteriorated during transfer, resulting in "cardiac and pulmonary arrest."

Later in the day, Nara Medical University hospital pronounced him dead. Abe was 67.

Read next: Funeral for former Japanese PM Shinzo Abe held in Tokyo