Okay got two characters, both twelve ish. They were raised by their grandmother to be her political tools, and during some grueling training she insulted their dead parents, and they killed her by accident. Would it be plausible for them to fool themselves into believing they wearn't responsible?
Absolutely. It's called rationalization. That's the concept that you use to say, "Oh, if I'm eating cookies at someone else's house, then they're healthy for me because I wouldn't normally eat food like that at home." So in the case of two twelve year-olds rationalizing their behavior here are some examples: "She was old and she would have died anyway." "She tried to kill us and we defended ourselves." "It's what God wanted." Just a few examples.
Some cases of amnesia are prompted by a traumatic event, where the person is so stressed by the idea of what they had done/what happened to them, that they forget everything about themselves. Some cases of dissociative identity disorder (D.I.D., known better as multiple-personality disorder) happens when a traumatic event causes the person to invent new personalities, such as a stronger but possibly more malicious personality with a different name. Sometimes they are aware of these other personalities, sometimes they are not. In your story, perhaps they could convince themselves that this other personality did it, not them (even though the new personality came later) Also, they could simply have delusions. Perhaps they invent a situation in their head, of some masked man coming from the woods, or the grandmother killing herself, etc. Overall, though I think having ONE child commit the crime will be ultimately more interesting and plausible. Especially if you choose one of the things I mention above. No way would both children develop D.I.D., and it is unlikely that both would come up with the same delusion or both get amnesia. I think having one will move the story into an interesting place where the other suspects the one who did it, but never says anything or whatever.
^This. If the denial is powerful enough, it can even result in developing multiple personality syndrome. "I didn't do it! Sammy did it!" (Sammy being the personality developed)
A twelve year-old may be smart. But if she causes the death of someone, however accidental, some psychological scarring will be involved. And whether or not it was her fault, if she doesn't recieve some kind of reassurance it's entirely likely that she will take the blame upon herself either way. No, if she's denying she did anything, I'd wonder how innocent she is. Beyond that, it's your story, so however it works out is up to you.
"We didn't do it. We didn't do it, ok? We didn't do anything. It just ... it sorta like just happened." "It just happened." "Yeah, it just happened." "You killed her." "No! We did not f****** kill her! We did not even actually touch her." "But you stuck a knife in her back." "We didn't touch her, ok?" "It's all right, you didn't touch her, the knife just somehow ended up embedded between her third and fourth ribs." "Look, can we talk about something different? Like, please?"
Well, they are responsible even though it was an accident. The question you need to ask is will they hold themselves accountable, or will they try to justify / rationalize / redirect their actions.
If O.J. can convince himself that he didn't do it, I'd have to say that anything is possible. At age 10 or so, I had convinced myself that I was going to be Spider Man when I grew up...and I believed it with the deepest conviction a 10 year old could muster. Therefore I'd say it is even more plausible when dealing with children characters. Side note: How does one "accidentally" kill someone who just insulted your dead parents? Would your explanation stand up in a court of law? Would a jury buy it as an "accident"? I'm just sayin'
Well their gran was coining spells at them (they're magic) and she started insulting their parents, the kid's flung a spell in self defense but the anger behind it unintentionally enhanced it.
At something like that, young characters could rationalize the event as a "we didn't mean to kill her, it wasn't what we wanted to do... the magic went out of control, must have, so it's the magic's fault, not our fault" and if the grandma character taught them magic, they could even further rationalize it to being the grandma's own fault for her own death. Denial is a very powerful thing in general, it's not too far-fetched for two twelve year olds to shirk responsibility for a death and even delude themselves to believe they didn't do it in the first place, anyway.
