I've been (and remain) quite a fan of yours, AA. In fact, I found WS via your Tumblr blog.
But I think there is a logical problem in your post above. We were inquiring into SMD's possible infatuation with LG for the purpose of determining (in our own judgment) whether that provided a motive for SMD to commit the homicide.
Your post says: IF there actually was a sexual component to this homicide, then -- in cases involving friends & acquaintances as victims -- then there is usually fixation. on the victim by the killer.
Your syllogism basically says IF SMD KILLED LG W/SEXUAL ACTS INVOLVED, then there was, indeed, fixation (lust & obsession).
That's fine, but it doesn't help us decide whether SMD killed LG w/sexual acts involved.
What I was trying to determine was: whether there was
independent evidence of an obsession/infatuation. I italicize
independent to highlight that I mean "independent of a guess that SMD did it." The purpose of my inquiry was to see whether there was any quasi-logical reason that SMD
might have a motive for homicide.
For those of us trying to determine whether we personally believe SMD did it, your statement that "If he did it, he was obsessed." just isn't helpful. It presupposes the conclusion we're trying to inquire into.
I hope that makes sense. I lost myself a couple of times in there.