What will happen if a legally dead but actually living person commits a crime after they are declared legally dead?
I wonder whether they will have a normal or posthumous trial. Or will they be tried only after their death status got overturned (which may take between a few months and never). Or they will not be tried at all because it is impossible for them to commit crime after death.
Being declared legally dead does not mean that you are dead; it simply allows your assets to be distributed as if you were.
If you turn up alive, you go through a bureaucratic procedure to have the record of your death removed, get a new driver's licence, etc. You usually don't get your assets back. If you happen to commit a crime during this period you get arrested, charged and tried just like everybody else.
You don't really need to "revive" that person. It's the same as if you had someone whose "real identity"¹ is unknown. I don't think they would have any problem to trial inmate #123 or the guy who claims to be Abraham Lincoln.
If instead of Abraham Lincoln (dead 1865), it's John Smith (dead Dec 2020) the one he claims to be, you would have the benefit of modern records of him (the crime scene shows the fingerprints, ADN, etc. of dead John Smith) but hey, here is another guy whose fingerprints also match those of the crime scene! So you could trial them.
It would seem preferably for them to be declared legally dead after being trialed for the crime (see e.g. Maggie Dickson), although in that case I still don't think it would be in their interest to be recognized as that same person.
¹ And what's a "real identity", anyway?
