That's the verdict from Ryan Davidson, a lawyer who focuses on the hypothetical legal ramifications of comic book tropes, characters, and powers at his blog, Law And The Multiverse.
"It depends on how the disease works," he said. "If zombies are effectively unconscious, then they would be incapable of performing voluntary actions and thus immune to criminal liability (or civil liability, for that matter). The zombies in the most recent 'I Am Legend' movie appear to be fully conscious, if perhaps a bit aggressive, so they could potentially be found liable. But in most others, probably not."
Davidson and his partner James Daily, will be discussing various legal aspects of being a zombie on Friday at WonderCon, a comic convention taking place in Anaheim, Calif. They will be joined by H. Eric Bender, M.D., Praveen R. Kambam, M.D., and Vasilis K. Pozios, M.D., three physicians specializing in forensic, child and adult psychiatry.
Daily said that a zombie apocalypse would be a mess for courts because the law sees consciousness as a black and white issue.
"From the law's perspective someone is either fully alive or fully dead; the law doesn't recognize the undead as a separate category (they are fictional, after all)," he stated by email. "I don't know that a separate category is necessary, though. In most zombie fiction, the zombies are either 'irreversibly deceased but reanimated corpses' or they are still-living humans whose behavior has been affected by supernatural means or a virus of some kind."
Davidson said there is also the question of whether zombies would have legal rights if brought to trial. He said it depends on how it reached the undead state.
"If 'zombies' are re-animated corpses, then no. The dead have no rights," he said. "But if 'zombies' are living people infected with some kind of virus, like in '28 Days Later,' then still have all the same rights they did before infection.
Friday's presentation will feature a mock trial with a former zombie and Daily said it's possible to argue that a person who is no longer undead could claim insanity for any crimes committed while in this brain-eating vegetative state.
"If the crimes were committed while they were a zombie, and if the zombie condition causes legal insanity (basically defined in many states as not knowing what you are doing and not knowing that what you are doing is wrong), then they would have an insanity defense, even if they were later cured," he said. "Some crimes have statutes of limitations that might run, but murder has no statute of limitations, and that's the crime most people are going to care about."
Pozios said the presentation is designed to explain legal insanity, a concept he says is often misunderstood.
"In order to be found legally insane, your mental state had to be so impaired that you didn't know that your act was wrong," he said. "A zombie would fit this description, although we are in no way equating people with mental illnesses to zombies.
"Featuring a now cured zombie highlights the fact that when it comes to legal insanity, a criminal defendant's mental state at the time of the act is what's relevant, not his or her current mental state during the trial. So, even if someone is perceived to be 'acting crazy' in the courtroom, that does not tell us about the issue of criminal responsibility."
Pozios concedes that the nature of the presentation forced them to use a former zombie instead of one currently in that state.
"A full-blown zombie would likely not be able to work with legal counsel or follow the trial, and thus would be Incompetent to Stand Trial," he explained. "Not to mention, it would be pretty difficult to assemble a jury of his peers."