Tokyo CNN  — 

The Unification Church said Monday it was puzzled by reports of alleged resentment held against the group by the man suspected of assassinating former Japanese Prime Minister Shinzo Abe.

“There is a big distance between having resentment toward our association and killing former Prime Minister Abe,” Tomihiro Tanaka, the Japan office chairman of the Family Federation for World Peace and Unification, told a news conference Monday.

“We struggle to understand why this happened. We will cooperate fully with the police to reveal his motive,” he added.

The church’s comments come after Japanese broadcaster NHK reported earlier in the day that the suspect, 41-year-old Tetsuya Yamagami, targeted the former Prime Minister because he believed Abe’s grandfather – another former leader of the country – had helped the expansion of a religious group he held a grudge against.

Abe’s grandfather Nobusuke Kishi, who served as Prime Minister from 1957 to 1960, was targeted for assassination in the final year of his premiership, though he survived after being stabbed six times.

“I thought that former Prime Minister Nobusuke Kishi contributed to the expansion of (the religious group), and I thought about killing his grandson, former Prime Minister Abe,” the suspect, 41-year-old Tetsuya Yamagami, told investigators, NHK reported.

“I had a grudge against a particular religious group, and I thought that former Prime Minister Abe had a close relationship with this group,” Yamagami reportedly said. “My mother got into a group and made a large donation and my family life was messed up.”

Yamagami has not been formally charged, but is being investigated on suspicion of murder after admitting to shooting Abe last Friday in the city of Nara, where the former leader had been delivering a campaign speech.

Tetsuya Yamagami, the suspect in the assassination of Shinzo Abe, walks out of a police station in Nara on July 10.

CNN has not been able to independently confirm what group Yamagami was referring to, or any links between Abe and any group the suspect harbored hatred towards.

However, on Monday, the Japan office chairman of the Unification Church said Yamagami’s mother had been a member who attended its events about once a month.

But Yamagami himself was never a member of the church, Tanaka said in a statement.

In a news conference later Monday, Tanaka said he had learned the suspect’s mother was having financial difficulties around 2002, but added: “We don’t know what the causes were or how they affected the family circumstances.”

CNN has not been able to locate Yamagami’s mother for comment, nor determine whether she has legal representation, nor to confirm whether she was affiliated with the church – a group that was founded in South Korea and gained fame worldwide for its mass weddings, including in New York’s Madison Square Garden.

Tanaka also denied that Abe’s grandfather had any role in expanding the Unification Church, saying Kishi did not take “any special measures or have any special influence on the spread of the religion at all.”

The church had received a message of support from Abe at an event it organized, but the former Prime Minister was not a registered church member, nor did he sit on its advisory board, Tanaka said.

What is the Unification Church?

The Unification Church, originally known as the Holy Spirit Association for the Unification of World Christianity, was founded by Moon Sun-myung in 1954. It rose to prominence in the late 1950s and early 1960s, an era of upheaval in South Korea, which at the time was transforming from a poor country torn apart by civil war to one of the world’s most modern economies.

By the 1980s the church had a global reach and it remains prominent in parts of Asia today. It continues to make international headlines for its mass weddings, in which thousands of young couples tie the knot at the same time, with some brides and grooms meeting each other for the first time on their wedding day.

A man prays at the site where Japan's former Prime Minister Shinzo Abe was shot during an election campaign on July 8 in Nara.

Moon, known by followers as “Father Moon,” died in South Korea in 2012 at the age of 92.

Who is Tetsuya Yamagami?