Three former sumo wrestlers and one of their mothers were indicted Wednesday for gambling on professional baseball.

Sadahide Furuichi, 34, formerly known as Furuichi in the second-tier juryo division, his mother, Yoneko, 63, and Tetsuya Yabushita, 29, a third-tier makushita division wrestler who was formerly known as Matsumidori, were indicted for allegedly hosting gambling sessions.

Shunsaku Yamamoto, 35, a makushita grappler whose ring name was Azusayumi, was indicted for assisting them.

Furuichi and Yoneko allegedly got four people to bet ¥280,000 in total last May, while Yabushita got six people to bet ¥520,000 between April and May 2009, according to the indictment. Yamamoto allegedly helped Yabushita in the process.

The gambling scandal involves several active wrestlers and has rocked the traditional sport. On Tuesday, police gave prosecutors their case on nine other players, including active wrestler Shironoryu, 27, and Daido, 28, both in the juryo division.

The Japan Sumo Association is in the midst of a probe into a match-fixing scandal.