Police on Saturday arrested a senior member of a Japanese crime syndicate and two others for allegedly taking bets on baseball games, including from former Yomiuri Giants players.

The arrests come as police step up their investigation of suspicions that money bet by professional baseball players helped finance criminal groups.

The three, including Masatake Miyake, 42, a member of an affiliate of Japan's largest crime syndicate, the Yamaguchi-gumi, are suspected of taking betting commissions on pro and high school baseball games between March and October 2014, with former Giants pitchers among their customers.

The involvement of a crime syndicate had been suggested during the trial of former Giants pitcher Shoki Kasahara, 25, who has admitted to helping a bookmaker facilitate gambling by collecting money from two other former pitchers.

Also arrested were 37-year-old welder Yoshimasa Sakai and Katsuyoshi Fukuoka, 36, a temporary worker. Both are former members of Yamaguchi-gumi affiliates.

Miyake denied part of the allegations, saying, "There are also customers I do not know. It's not that I did everything," according to the police. Sakai and Fukuoka admitted to their charges.

The three allegedly collected a total of ¥1.4 million ($13,860) in bets on 25 matches from seven people, including the bookmaker, Satoshi Saito, investigative sources said.

Saito, 38, a former restaurant operator, has also been tried for taking commissions on bets from Kasahara and the two other former Giants pitchers Ryuya Matsumoto, 23, and Kyosuke Takagi, 27. Matsumoto and Takagi paid fines last month for the gambling.