Photo/Illutration Chief Cabinet Secretary Hirokazu Matsuno responds to a question at the Dec. 8 Lower House Budget Committee session. (Takeshi Iwashita)

Prosecutors are looking into whether Chief Cabinet Secretary Hirokazu Matsuno failed to report income from a suspected slush fund of the ruling party faction once led by former Prime Minister Shinzo Abe, sources said.

Between 2019 and 2021, Matsuno was secretary-general of the Abe faction in the Liberal Democratic Party. In that role, he oversaw all administrative matters related to the faction, including if the slush fund existed.

According to inside sources, Matsuno may have received about 10 million yen ($69,600) in “kickbacks” over five years from that slush fund.

Abe faction members were given quotas to fill for ticket purchases to its fund-raising parties. The size of the quotas depended on how long the members served as Diet members or if they held an LDP or faction post.

Amounts collected that went beyond the ticket quotas for each faction member were placed in a slush fund, and faction members, in turn, received kickbacks for the amounts above their quotas, the sources said.

Over a five-year period between 2018 and 2022, about 100 million yen was accumulated in the slush fund, according to the sources.

The amounts over the quotas that went to the slush fund were not listed in the Abe faction’s political fund report as income. The money returned to faction members was also not reported by the faction as expenditures.

The faction members, including Matsuno, also did not report that money as income, the sources said.

Prosecutors have already questioned a number of Abe faction officials in their investigation into possible violations of the Political Fund Control Law.

Matsuno became chief Cabinet secretary when Prime Minster Fumio Kishida took office in October 2021.

Since the story broke about the suspected slush fund in the Abe faction, Matsuno, the top government spokesman, has been asked on a daily basis at his news conferences whether he received kickbacks.

He has consistently replied that because the matter involved factions he could not respond from his position as a government official.

Opposition lawmakers asked Matsuno the same question at the Dec. 8 Lower House Budget Committee session.

Matsuno said his political organization was looking into the matter.

He added that he had no intention of resigning as chief Cabinet secretary.

At the same session, Kishida was also asked if his LDP faction had a similar slush fund, but he refrained from responding on grounds that prosecutors were continuing with their investigation.

Kishida announced on Dec. 7 that he was stepping down as a faction leader in part because of the scandal involving the fund-raising parties.

Some veteran lawmakers said Matsuno, given his important position, would also likely have to step down since he has not directly addressed the allegations of receiving kickbacks.