bbm
I'm thinking in case Abby/Libby:
If a killer kills for a motive, he doesn't want anybody to know, because it would meet with incomprehension much more than every other motive, the (smart!) killer could choose a manner of doing the murder, that is pointing to false motivation/reasons. The killer can possibly "enjoy" his thrill-kill without having sexual motivation, but he stages the scene like there had been sexual motivation, like an artist, who is arranging a still life so-to-say or a gamer, who plays a strategy game. Well, that the killer has low esteem for the female sex, he can't deny, if his victims are always girls/women. But that he has no real sexual interest, he can cover up. It would lead police/analysts in a wrong direction over months/years. If the killer has a girlfriend/fiancee/wife, it would be another aspect, not getting onto the police/FBI poi-list very fast.
Or do you all here think, that isn't makeable, that there was no real sexual motivation, if it looked like that at the crime scene?