Is Robert Mueller pursuing justice or perverting it?

I have serious doubts about Robert Mueller.  What is it exactly he's suppose to do now?  According to numerous people, including his good friend James Comey, no evidence exists of Donald Trump colluding with the Russians to affect the presidential elections. 

 So what is there to investigate?

Is Mueller looking at possible crimes committed by his friend Comey given the fact he admitted to leaking government work product to the press?  Will he do that to his buddy?  Or is Mueller conducting a bogus investigation in pursuit of process crimes to justify his paychecks that are already a waste of taxpayer money?