I think this is going to fizzle. The thing is that Salazar is all about skirting the legal line, doing everything he can while keeping the tests coming back clean. Apparently he thinks if you're testing negative, you're not cheating.
And even if most of us know this is immoral and against the spirit of the sport, there's no definitive smoking gun here and probably will never be.
I think the way forward is to stigmatize his group enough that runners (and maybe even sponsors) don't want to be associated with it, not for fear of testing positive but because of the backlash, distrust, and stigma.