Someone may have already mentioned this, so apologies if it is redundant.
I think I remember reading or discussing somewhere (my best guess is either in a criminal psych textbook or else on here in relation to Mickey Shunick?) that when a predator has a powerful, active inner fantasy world or life, he will plan out the crime to imitate that fantasy which he has, in his mind, rehearsed many times in excruciating and vivid detail, often including how he identifies/selects, pursues, and acquires his prey. But the fantasy often ends when the act is over. That means, unless it is a person who includes staging, cat-and-mouse games, etc., considerably less planning goes into the "clean-up."
I apologize if I have offended anyone by referring to prey and clean-up. I'm also sorry I can't come up with a source for this general memory I tried to paraphrase for yas...if it is from a criminal psych or profiling textbook, I don't own those, I only borrowed them and read them "for fun" while I was doing a project on a different campus. :/
ETA: my info was in support of the quoted post. But maybe rougelatete (sorry if I've misspelled your name- autocorrect repeatedly corrected me to "rouge later" and now I forget the right spelling) or PensFan could correct me as needed?