Police served fresh arrest warrants on Sunday to a former sumo wrestler and two yakuza linked to Yamaguchi-gumi, the nation's biggest crime syndicate, for allegedly trying to extort ¥100 million from former ozeki Kotomitsuki to keep quiet about their gambling activities, investigative sources said.

The Metropolitan Police Department served the warrants on former sumo wrestler Mitsutomo Furuichi, 38, and mobsters Yoshihiko Yasuda, 45, and Satohiro Mantani, 37.

The two yakuza demanded ¥100 million from Kotomitsuki during a March 27 visit in Osaka, saying they would expose the names and photographs of sumo wrestlers and elders who had been gambling for the past four or five years if he did not comply, the sources said.

Kotomitsuki refused to yield to their threats, they added.

The Tokyo District Prosecutor's Office meanwhile indicted Furuichi and Yasuda the same day in connection with a ¥3 million extortion case involving a 35-year-old former wrestler from the Onomatsu stable who allegedly arranged wagers on professional baseball.

The prosecutors, however, delayed the case of a 34-year-old yakuza arrested on suspicion of being an accomplice, because there was no solid evidence to corroborate it.