The man accused of shooting former Japanese prime minister Shinzo Abe tested a gun at a facility once used by the Unification Church.
The church, also known as the Family Federation for World Peace and Unification (FFWPU), said in a statement late on Tuesday (July 12) that Tetsuya Yamagami "test-fired his homemade weapon the night before the assassination at a building that was formerly used" by the organisation.
"Fortunately, no one was hurt," it said.
The group reiterated that the murder suspect's mother was a member but he was not, and that it was cooperating with investigators.
The Unification Church - long accused by critics and former followers of shady finances and policies that empty the pockets of members - has been a focus of attention since Mr Abe was gunned down.
Japanese police told reporters Yamagami blamed a religious group for his family's financial woes after his mother made large donations, resulting in her bankruptcy.
"Mr Yamagami's reported allegation that his mother's donations to FFWPU caused family problems is a matter to be investigated by the police," the group said. "Whatever his grievances, we wholeheartedly condemn violence and murder."
It also said Mr Abe sent brief remarks to two online events it held in the past year.
The 41-year-old suspected gunman, now in police custody on a murder charge, told the authorities he wanted to kill a senior member of the Unification Church, but targeted Mr Abe because he believed the former leader had close connections to the group's religion.
The suspect likely watched videos of the messages from Mr Abe to the group, Kyodo News reported on Wednesday.
Mr Abe, 67, was shot twice at close range last Friday by a man who approached him from behind. He was at the time making an election campaign speech for his ruling Liberal Democratic Party outside a train station in the western city of Nara.
Founded in South Korea by the late Sun Myung Moon in May 1954, the religious organisation known as the Unification Church has branches around the world, including in Japan and the United States.
Mr Moon, who declared that he and his wife were messiahs, was convicted of tax evasion in the US in the 1980s. He died in 2012.