TL;DR: Depends on the circumstances.
As someone pointed out, we usually think someone is culpable for a false belief when they are to blame for it (that's what culpable means, deserving blame).
That is kind of having it backwards. Not sure if you meant that, but it sounds as if the punishment signifies the guilt, when it should be the other way around, the guilt is the prerequisite for the punishment. Culpability describes the degree of agency and in turn moral and legal responsibility of a person regarding and action or inaction.
So the court has to check whether the action is legal/illegal, whether the accused can reasonably be framed as the cause of that action/inaction, but usually that is not enough to ascribe a fault/guilt/"culpa" of the accused. Like say a driver hits a pedestrian with a car and the later dies.
Now that could be because a tree fell on the road and the driver quickly reacted to safe their own life. It could be because the driver was texting or speeding and wasn't able to correct break or take a turn in time. It could be the driver having a stroke or some spasm and being incapable of reacting. It could be because the driver was drunk and thus incapable of reaction in time. The driver might have intended to harm, but not kill the other person. Or the driver might have actually murdered that person.
All these examples describe the same outcome, where the action or inaction lead to the death of another person and in all these cases it really ultimately is the driver who ends that person's life, because if they weren't on the road the other person would still be alive. Though we would rank the guilt of the driver very differently in these situations.
The thing is, the idea of blame and punishment in a legal system is to encourage or discourage certain behavior. So if an action happens involuntary, accidental or because of a lack of better options, then there's not really any benefit in blame or punishment as it's not within the realm of options of that person to act different from how they have acted, so praise or blame were never able to have any influence on that in the first place.
You could of course go to probabilistic models and hope that general blame or praise for a deed regardless of guilt makes people avoid or seek particular situations regardless of their lack of agency within them, so you'd idk further courage or cowardness, which depending on the situation might also be called reasonable caution and stupidity, so not sure how useful that is. Or people might realize that the application of law is essentially erratic and either go insane trying to abide by it, fixing themselves when their environment is the problem. Or they might try to fly under the radar and not bother with not breaking the law but rather with not getting caught. So rather than order you likely only create something that superficially seems ordered while internally following a ton of different paradigms, meaning any change or absence of change in the face of stress to the system can have completely unpredictable consequences.
Hypothetical and odd scenario. Person A is tricked into thinking person B is threatening them, and so destroys both their lives. Person A can very easily check if it's real, but refuses to. Person B can do nothing further than they already have.
Now with regards to being tricked into thinking there's an enemy when there isn't. Could you give an example of that being "easy" to check?
Because that's a huge problem that it's usually not easy to check. Like if someone poses a mortal threat to you, real or fake, then going to their house and getting to know them, having a nice chat and finding out they're a decent person, is not "easy", in fact it's playing with your life.
Like the more tangible the danger, the more you'll be in panic mode and not think straight. Which is apparently a common theme in scams where they keep people occupied and under tension so that idk you pay the bail for your child, before realizing "wait a second I don't even have children". Or realistically before realizing the other person hasn't even mention the name of your child or anything identifiable that relates to you and couldn't apply to a large percentage of other people as well.
Also the more another person is presented to you as a mortal threat, the less likely you are inclined to get to know them and find your prejudices invalidated. You know because that's dangerous (to the scammer, and so they make you believe it's dangerous to you). Now to a bystander that likely looks absurd because you could fairly easy see there is no danger and there is no danger in seeing that, because there never was one to begin with.
But likely that person needs to make the step of accepting that it could be safe before verifying that it actually is. Which takes courage, which is what a person on whom fearmongering has worked likely doesn't have in huge quantities.
Also with regards to something as vague as a threat, how do you disprove that? Like you can always go into paranoid mode and claim "that's just what they want you to believe". You know falling victim to externalized or at some point internalized framing. Like the other person says something absurd to make a joke and to break the ice and you thinking of them as evil read that as "damn he must be powerful so confidently saying the quite part out loud". In the worst case person B can not do anything at all that is not perceived by person A as a threat, because they already have that preconception and fit the facts to the narrative rather than the other way around.
So depending on how strong their fear and obsessions have grown it might not be easy for them at all, despite it being super easy for anyone else. Not to mention that whatever you bring forth as evidence that the feeling of a threat is unfounded, it's impossible to make that point with certainty. Life is inherently risky even if a particular risk is very very low.
I mean in the way I described it you might actually call it "tragic", which is a combination of evoking pity and anxiety.
But they could also wanted to harm B in the first place and the trickster just gave them a justification that they didn't check because they either wanted them to believe or just thought it would make for a good excuse if they weren't alone in the aversion of B.
So yeah in the end it depends on the actual circumstances...