that is why he ensures there is no paper trail.
Part of the reason BALCO got busted was because the investigator guy went through trash and found order forms for 'roids, needles, etc.
Lack of evidence doesn't mean evidence of absence....but legally lack of evidence is a problem. WADA suspected the Russians for a long time, but the whistle-blowers provided the evidence (video and other) to pursue a case. I'm sure if they had evidence in the other sports like XC skiing WADA would fully pursue and reveal the full scale of the Russian doping problem. That's why it's so unfortunate that the RUSADA guy was murdered as he was going to reveal so much more.
Inaccessibility of training sites in Kenya and Ethiopia + others is definitely a huge problem in terms of anti-doping. No testing and advanced notice testing makes it a joke.
Mo Money Mo Problems!