Taking PEDs isn't a criminal offense. Defrauding a government agency (the Postal Service) out of millions of dollars in sponsorship dough with race results helped by fraudulent means becomes racketeering. Using team sponsor money to buy PED's by putting it through secret bank accounts becomes another felony (money laundering). It's not the PEDs they're getting him on, it's the criminal fraud aspect. Again, had this suspected offense been perpetrated on a private corporation nobody would be investigating anything.