 FACT: Double jeopardy does not work in the way described in the  film. The same jurisdiction can not put you on trial for the exact  same crime under the exact same law, but other jurisdictions can if  you also violate the law there during the commission of your crime.  The killing of the husband, had it been murder, would have been a  second crime committed in another jurisdiction (moreover, it would  have been a second, distinct crime). She could have been put on  trial and sent back to prison (though presumably the original  sentence would have been cancelled).