A third-party panel that has been investigating a possible connection between the Kyoto-based Ohsho gyoza (dumpling) restaurant chain and a yakuza syndicate Tuesday released a report revealing the firm had been involved in improper transactions in the 1990s totaling some ¥26 billion.

The report said Ohsho Food Services learned of the transactions in November 2013, a month before then-President Takayuki Ohigashi was gunned down outside the firm's Kyoto headquarters, but failed to disclose it.

The panel, set up in January, found that some ¥20 billion had been improperly paid in connection with transactions with the head of a certain company group in the 10-year period starting in the mid-1990s.