Three gangsters affiliated with the Yamaguchi-gumi, the nation's largest crime syndicate, were arrested Sunday for allegedly extorting millions of yen in hush money from a former sumo wrestler from the Onomatsu stable who brokered the illegal bets rocking the traditional sport, according to Tokyo police.

The Metropolitan Police Department's organized crime division also served a fresh arrest warrant to another former wrestler, Mitsutomo Furuichi, who has been charged with extortion in the betting case, which mostly focused on pro baseball.

The four together are suspected of threatening the unnamed 35-year-old former wrestler by saying the active junior wrestlers in his stable would be booted out of sumo if his gambling came to light, investigative sources said. The Japan Sumo Association association bans wrestlers from gambling.

The man retired as a wrestler in 2006 and is believed to have managed the gambling of former top-division grappler Kotomitsuki and former stablemaster Otaka, who were dismissed over the issue last month, the sources said.

The man was quoted as telling police during voluntary questioning that a gangster in Nagoya who was affiliated with Yamaguchi-gumi served as the bookie for baseball bets but died about a year ago, they said.