Tokyo prosecutors raided the head office of Daiwa Securities Co. on Sept. 18 to search for evidence of payoffs allegedly made by the major securities firm to corporate extortionist Ryuichi Koike, a "sokaiya" central to similar scandals involving Nomura Securities Co. and Dai-Ichi Kangyo Bank.

The Securities and Exchange Surveillance Commission and the Tokyo District Public Prosecutor's Office suspect that Daiwa paid 54-year-old Koike more than 67 million yen by mid-1996, which constitutes a violation of the Commercial Code and the Securities and Exchange Law, sources said.

Sources say that Daiwa executives questioned previously by investigators have owned up to the payoffs, the sources said. The operation comes on the heels of the arrests Sept. 17 of five former and present executives at the Yamaichi Securities Co., as well as the indictments of three Nomura Securities Co. executives who have all recently been linked with payments to Koike.