Having a clue about it and being able to reliably test for it are two totally different topics. Just because WADA may know about a drug and suspect riders are using it doesn't mean they have a means to catch them doing so.
I just have a really hard time believing anybody is clean these days, and it has nothing to do with Lance getting caught. Because of all of the revelations that have come out and the success in identifying doctors and trainers who were linked to doping, just about anybody who wins anything these days has somebody working for the team who has some past tie to doping. With the number of times we later find out the winner was dirty, it is almost to the point when I am surprised to not hear about them later being busted. I can't totally convince myself that Wiggins poor showing this spring is totally unrelated to Leinders no longer working with Sky. Sad state of affairs for the sport, but I won't quit watching.