Double Jeopardy is a 1999 legal thriller starring Ashley Judd and Tommy Lee Jones. The trailer introduces Judd's character, Libby Parsons, as a woman who is in prison for a crime she didn't commit—the non-existent murder of her husband, Nick.
One of Libby's fellow inmates gives her some interesting legal advice: If the state says Libby's already killed her husband, they can't convict her of it a second time. Libby is free to kill Nick when she gets out of prison and there's nothing the authorities can do about it.
After being falsely accused and wrongfully convicted of murdering Nick, Libby learns that he was only faking his death. When she is finally released on parole, she sets out to find her son and settle the score with Nick. At one point she tells him, "I could shoot you in the middle of Mardi Gras and they can't touch me."
The prohibition against double jeopardy is real. The government can't prosecute someone more than once for the same offense. But, here, if Libby were to kill Nick when she gets out of prison, it wouldn't be the same murder that sent her to prison in the first place. Sure, the same victim is involved, but the alleged murders would have occurred at different times and places—they're not the same offense.
We look to Hollywood for fantasy, and the legal premise underlying the movie Double Jeopardy is just that—a fantasy.
Another legal question that some viewers of Double Jeopardy might have is whether Libby could have been convicted of murder in the first place if Nick's body was never found. And while it's difficult to convict someone of murder without a body, it is possible. Prosecutors use circumstantial evidence—for example, the fact that the victim has been long missing and has never contacted loved ones—to prove that the victim is dead.