Won't find many who know more about doping either to be honest.
Seriously though, that Fuentes had doping programs in place for several Spanish clubs is the worst kept secret in football. It's not even a secret because he showed them to Stephane Mandard back in -08. Betis, Sevilla, Real, Barcelona, Valencia - all of them involved. The only thing that the story resulted in was that Le Monde were forced to compensate Barca and Real for libel in 2011. Fast forward two years and Fuentes is involved in one of the biggest doping scandals in history. He's on record saying that Spain would be stripped of their World cup medals if he were to reveal some of the names he doped up (which might well be bullshit, but let's take it at face value considering who he is).
And it's not like Fuentes is the only one out there. Just google Luis GarcĂa del Moral and his connection to Spanish football. The entire league stinks.