Ariana's death

[Carol]

No: HPFGUIDX 177164

I'm curious as to what others think regarding Ariana's death.
Dumbledore himself isn't sure what happened and Harry doesn't want to
know. Obviously, JKR didn't want to tell us, either. She deliberately
left it open to speculation. To me, it seems most likely that
Grindelwald killed her (probably aiming at Aberforth), but if the
spell he cast had been an AK and the brothers knew they hadn't cast
one, the identity of the killer would have been obvious, at least to
them. Gellert's conduct (fleeing the scene) indicates that he either
was guilty, feared he was guilty, or thought that the others would
suspect him of being guilty.

Anyone care to speculate on what actually happened? Who cast the spell
and what was it? If it was Grindelwald, was he trying to kill
Aberforth, or did his magic completely escape his control?
(Apparently, an AK isn't the only spell that can kill. Ariana managed
to kill her mother through accidental magic.)

Assuming that Albus didn't actually cast the spell, to what degree is
he responsible for his sister's death, in your view?

Carol, wondering why there's been so little discussion of DD's youth
and a certain merry-faced boy