The second example was conditional on your thinking "definitely B" about the first example. Since that wasn't your reaction to it, I'm not particularly surprised that you didn't find the second example difficult :-). Of course it's not the same as the original story; what would be the point of offering something that was? I suppose my higher-level point is that by tweaking stories of this sort one can generally find situations in which any given person can't give a confident verdict of the form "A rather than B killed him".

The whole thing's a digression anyway...