Frankly, the outcome of this FBI investigation could also be that the administration is cleared in the end.
At this point, if he wants to ever be an effective President (doubtful), Trump needs the FBI investigation to clear him, so that he can move past Russiagate. That he and his supporters are not confident that an investigation (by the man who more than any other individual handed Trump the Presidency, no less) will clear Trump says volumes. His followers think he's guilty (not that they'll admit it), and he and his cronies obviously have things they want to keep hidden.
Trump's clumsy, desperate-looking pushback and maneuvering against the Congressional and DoJ investigations is what convinces me that he is guilty, more than anything else.
Firstly its not the job of the FBI to 'clear' people. Their job is to investigate and the most they can do is declare that they have found no evidence against someone. They've already said they have no evidence so far against Trump and his team and it hasn't stopped the Dem witch hunt.
Secondly if you think that the behaviour of Trump and his supporters is that of people who know he's guilty and are worried about being found out then please explain how their behaviour differs from people who think that the Dems and their allies in the deep state are working to get him out of office by framing him for something that he's not guilty of?