Washington Revised Code Title 10. Criminal Procedure § 10.43.040. Foreign conviction or acquittal

Whenever, upon the trial of any person for a crime, it appears that the offense was committed in another state or country, under such circumstances that the courts of this state had jurisdiction thereof, and that the defendant has already been acquitted or convicted upon the merits, in a judicial proceeding conducted under the criminal laws of such state or country, founded upon the act or omission with respect to which he or she is upon trial, such former acquittal or conviction is a sufficient defense.  Nothing in this section affects or prevents a prosecution in a court of this state of any person who has received administrative or nonjudicial punishment, civilian or military, in another state or country based upon the same act or omission.