Most people say McCain did it. McCain is from Arizona so is Flake. Doesn’t seem too far fetched to me..
Google McCain McMullin photo then click images.
McCain got involved after the anonymous Republican donor and the unidentified Democrat client. Somebody showed him the prepared dossier. He didn’t order it, though he did show it to people. No reason why Flake would be involved. It’s up to you to prove he was, not to other people to prove he wasn’t.