Legal Question in Criminal Law in California

A wrongful conviction may be attacked by a petition for writ of habeas corpus. If there is enough evidence to prove the prisoner is truly innocent, a judge could reverse the sentence and set the inmate free.

If the court decided the person truly was innocent, then the sentence wouldn't be reduced... it would be over, and the prisoner would be released.

The person who confesses could be prosecuted. Due to the high degree of proof needed to overturn a conviction on these grounds, the person would have to give a pretty convincing confession. In California, there is no statute of limitations on crimes punishable for life in prison, so it doesn't matter how much time had passed.

The answer depends on who you are, and why you're asking. If you committed the crime, leave well enough alone and keep your mouth shut, there's no guarantee the other individual's case will be reopened, and you really don't want to volunteer for life in prison. Or maybe you are just hearing the usual BS story told by 100% of convicts about how innocent they really are.

There would have to be some evidence, other than a confession from some stranger. I can think of numerous examples, such as the fellow who "confessed" to killing Jon Benet Ramsey, just to get a free plane ride form Thailand.