Huber prosecutes in his Utah district. The AGAC of which he is a part advises the AG but does not prosecute anyone.
Grand jury witnesses are not bound to secrecy. Politically charged grand juries become known very quickly, both from witnesses and from people such as journalists and bloggers who stake out federal courthouses looking for known political actors.
Just so I don’t misunderstand - are you saying that because there have been no leaks about grand juries other than in Arkansas, there are no grand juries going after anyone big? Or are you meaning something else?