i'm missing the fourth! i don't know if the basilisk counts as violent. well, it hypnotized her by magic, but then it squeezed her to death and ate her, so in fact she died by being crushed to death. that could count as non-magical violence since it's practically the same as being crushed under a house or a giant anvil.

maybe it has to do with the speed of death? whether you expected you were about to die or not?