My guess is it's mainly another "the process is the punishment" case with a goal to force him to resign or give an excuse to fire him.
> I think he would have to have conveyed information about the investigation not known outside of it.
No, I’m pretty certain that’s not the way it works. That is certainly not the way it works for classified info — a security clearance holder is not allowed to confirm (or deny) classified info that may be known (or at least suspected) from other non-classified sources (e.g. news stories, etc.) I’m pretty certain the same principle applies in this context.