Police have searched the homes of a member of the founding family of the Gyoza no Ohsho fast-food chain and others in connection with the 2013 killing of its president in Kyoto, investigative sources said Wednesday.
The police are looking into potential links between the family member, a former Ohsho Food Service executive in charge of accounting, and the murder of Takayuki Ohigashi, 72, then head of the company.
A third-party committee has pointed to dubious deals between the fast-food chain and a specific business group.
The police have already questioned the manager of the business group, an acquaintance of Ohsho's founding family who operated a golf course in Fukuoka Prefecture, according to the sources.
The police have also questioned other former Ohsho executives, they said.
The developments came after Yukio Tanaka, 56, a member of a group linked to the Kudo-kai yakuza crime syndicate, was arrested last week on suspicion of fatally shooting Ohigashi in a parking lot in front of the company's head office in Kyoto on Dec. 19, 2013.
Ohsho Food Service set up the third-party committee following reports that the company may have had ties with criminal organizations.
Although the panel said in March 2016 it had not uncovered links between the company and crime groups, it noted there had been questionable deals worth around ¥26 billion ($176.40 million) prior to Ohigashi becoming president.