As I recall, he said no reasonable prosecutor would bring the case, which was clearly absurd.
His handling of this entire affair has been disgraceful. For some mysterious reason, he directed or allowed the investigation to be deliberately botched. They violated elementary procedures, handed out immunity for no good reason and allowed the destruction of evidence.
Now he finds himself painted into a corner with more damaging evidence coming to light in the most embarrassing manner conceivable, on the notorious Weiner's computer. So he tried to cover his butt with his letter to congress, infuriating democrats who thought they had buried the investigation.
We have not seen the end of this, at least not if Trump wins. He will appoint a special prosecutor, but it will take years to unravel it all.