TOKYO — The Japan Sumo Association says that random doping tests given to wrestlers last month are all negative.

The JSA started conducting random tests in April after second-division wrestler Wakakirin was arrested on suspicion of possessing marijuana in January. Wakakirin was the first Japanese wrestler to be arrested in a marijuana case and the latest to be thrown out of the sumo world.

A total of 103 wrestlers, coaches and other sumo officials who underwent urine tests on April 22 all returned negative results, the JSA said Thursday. The wrestlers, including grand champion Asashoryu, were checked for three types of illegal drugs, including marijuana and methamphetamines.