CrR 4.3: JOINDER OF OFFENSES AND DEFENDANTS
(a) Joinder of Offenses. Two or more offenses may be joined in one charging document, with each offense stated in a separate count, when the offenses, whether felonies or misdemeanors or both: (1) Are of the same or similar character, even if not part of a single scheme or plan; or (2) Are based on the same conduct or on a series of acts connected together or constituting parts of a single scheme or plan.
(b) Joinder of Defendants. Two or more defendants may be joined in the same charging document:
(1) When each of the defendants is charged with accountability for each offense included;
(2) When each of the defendants is charged with conspiracy and one or more of the defendants is also charged with one or more offenses alleged to be in furtherance of the conspiracy; or
(3) When, even if conspiracy is not charged and all of the defendants are not charged in each count, it is alleged that the several offenses charged:
(i) were part of a common scheme or plan; or
(ii) were so closely connected in respect to time, place and occasion that it would be difficult to separate proof of one charge from proof of the others.
(e) Improper Joinder. Improper joinder of offenses or defendants shall not preclude subsequent prosecution on the same charge for the charge or defendant improperly joined.