"Murder Isn't Always a Crime" claims the tag line for the new movie Double Jeopardy, in which Libby Parsons (Ashley Judd) is framed by her husband in his faked murder. Upon her release from prison, she plans to kill him--for real, this time--since, as everyone knows, you can't be prosecuted twice for the same crime. If this plot were real, could Libby get away with it?
Legal precedent for these circumstances is lacking. However, most legal experts agree that the Libby would go back to prison for the second murder--even though the court's records would show that she was convicted of killing the victim years ago.
Libby's defense in the movie--double jeopardy--is derived from the Fifth Amendment of the Constitution, which says that no person "shall be subject for the same offense to be twice put in jeopardy of life or limb." Libby's problem is that double jeopardy can only be claimed when multiple prosecutions arise from a single criminal action. For example, a double jeopardy defense would certainly fail if a defendant claimed that he couldn't be prosecuted for a second assault on a victim just because he was convicted of assaulting her two years earlier.
The obvious objection to this analogy is that, while you can clearly assault someone twice, you can only kill a person once. Therefore, the evidence that would prove Libby's guilt in one crime would necessarily clear her of the other. The problem with this defense is that the court is free to overturn or disregard earlier factual findings if new evidence--say, a recently killed body--proves them to have been incorrect. (Libby would have welcomed this flexibility if the court had discovered that her husband was alive while she was still imprisoned.) If the state (or Libby's defense lawyer) grossly mismanaged the first case in a way that resulted in her wrongful conviction, she might be able to sue for damages. But it would not affect her second trial.
If convicted in a second trial, Libby might argue that she had already served her time and should be set free. Depending on the state in which the murder was committed, the court might have some leeway in reducing Libby's sentence. But convicted murderers are almost never given suspended sentences, and in Libby's case the circumstances might increase her punishment because the murder was premeditated.
Explainer thanksSlatereader Mason Stockstill for suggesting the question and King County (Washington) Superior Court Judge William Downing for helping to answer it.