State v. Hofstetter
In State v. Hofstetter (1994) 75 Wn. App. 390, 401 [878 P.2d 474, 481 & fn. 10] , the prosecution advised two witnesses not to speak to defense counsel unless a prosecutor was present and also threatened to withdraw its plea offer.
The court found prosecutorial misconduct but also held that "it is improper for a prosecutor to plea bargain in such a way as to impose such instructions or advice on a witness. At least in the absence of extraordinary circumstances, the fact the State is prosecuting a case against the witness does not alter the State's duty not to obstruct access to the witness in the case against the defendant." (Id., 878 P.2d at pp. 481-482.)