in 2003, barry bonds became embroiled in a scandal when greg anderson of the bay area laboratory co-operative (balco), bonds' trainer since 2000, was indicted by a federal grand jury in the united states district court for the northern district of california and charged with supplying anabolic steroids to athletes, including a number of baseball players. this led to speculation that bonds had used performance-enhancing drugs during a time when there was no mandatory testing in major league baseball. bonds declared his innocence, attributing his changed physique and increased power to a strict regimen of bodybuilding, diet and legitimate supplements.