I can't decide exactly how the victims die. The choices have been whittled down to three or four, and the final decision will change the course of the story, but I can't find out enough about certain murder methods to make that decision. I suppose it's only right that information on how to kill people is not readily available. My non-writing friends think I'm weird enough as it is, but it is only fiction, after all.
Anyway, I've decided to push through and write the story anyway, trusting that the exact method needed will become clear as the plot elements mesh. I've done this before and it works for me: looking back is sometimes the clearest way to see everything, and in fiction, unlike real life, I can change the past.