of obstruction of justice or conspiracy, but in general there is no prior restraint on speech. Perhaps someone would be required to sign a non-disclosure if information was being provided as part of the questioning, but I would refuse to answer any questions under that condition.

It would take a Court order to silence someone.

I am just speculating though. Any lawyers want to chime in?

if law enforcement asks them not to disclose the contents of the interview. Also the U.S.A. and witness lawyers often work things like that, and immunity issues, out prior to submitting to an interview.

i do know that they can't keep witnesses quiet regarding their own testimony *after* the grand jury is done.