[Catfish]

Ah, now he has been poisoned ? I have read this different before in russian media.

Yes, it cannot have been Putin because as russian protesters proclaimed "poison is the weapon of a woman, a coward and a eunuch!"
I guess you do not see sarcasm so easily, but believe me, this is.
What is true however is, that the whole transport and medical aid would not have happened without Putin's approval, for whatever reason he did that..

So you say Navalny is no challenge for Putin. Who would be a legal and approved (by Putin??) candidate for the next russian president? If we exclude Medwedew.