They also don't find stuff. Which is kind of the point really.
It's worth reminding ourselves what the decision to close the Fed case means and what it doesn't mean. It means a decision has been made not to pursue a case of taxpayer's money being used to pay for doping. It does not mean that Armstrong has been declared innocent or exonerated from this, especially as it is being reported that it is the press leaks of evidence that have proved to be the death of this investigation, not a lack of evidence.
It also has no bearing in whether he doped, and was not about that in the first place. Doping is not a federal offence in the USA. That is a job for the sporting bodies.
In the light of the last few editions of the Tour in which not only the top guys, but pretty much everybody, have been so close together, and those Armstrong style rampages that go on and on just haven't happened, does anybody actually still believe that Armstrong (and everybody else) wasn't brimmed to bursting with doping?