You can't lie to a GJ.

But you can take the 5th, as a constitutional protection against self incrimination.

The basic tools a GJ has to make you talk is the threat of being put in jail for non-cooperation.

The fact of whether or not he is a "journalist" doesn't seem to be of any consquence. I don't see any thing that would tell me a reporter can withhold evidence from a GJ.

  I do not believe that being a member of the press (I would define that broadly even to include "amateurs")  means that one has an absolute privilege to withhold information from proper command of a court to disclose.

  I also do not believe that a court should order disclosure of the work-product of a member of the press absent a showing of a compelling need for the information in an important matter.

   Among a non-exclusive list of things that should be considered:

         -- is it the statements made to the reporter after a pledge of confidentiality which would buttress claims of privilege?

          -- Is it a record of something that actually occurred in public which obviously detracts from any confidentiality based claims of privilege?

     -- Is it information which can only be obtained from  the reporter?

   -- Is the content of the information related directly to the known target of an investigation which has a substantial evidentiary basis for alleging specific crime[s] -- as opposed to some degree of a "fishing expedition" where the investigation is an amorphous into whether some unidentified people might possibly have done something that might possibly be a crime (there are a lot of degrees here)

  -- the degree to which the party seeking disclosure can establish its direct relvance to the investigation.

  -- the seriousness of the alleged offense under investigation- mass murder is different than breaking a window.

  -- the prior uses to which the reporter has put the information. For example, was it deep background that he never even reported with attribution to an anonymous source was it reported and attributed anonymously, was it actually reported with identification of the source, etc?

  These are a few examples of what I think a court should consider when conducting a case-by-case balancing test and i do think the burden of persuasion should be on the party seeking disclosure.