I wish I could spread this gospel far and wide. We don't know what the Idaho killer (who is, I think, BK) would do or not do, beyond committed mass murder. That already makes him outside my understanding.
Plus, even within the national database of mass killings, kept by Northeastern University's Department of Criminology & Criminal Justice, BK is unusual.
Apparently, unlike Ted Bundy - whom BK knew a lot about - BK started out his career of crime with a mass murder. But like Ted Bundy, he targeted sorority girls (apparently). So he shares some things in common with Bundy - and with Elliot Rodger.
He also may share things in common with EARONS/GSK (DeAngelo), because of his interest in police work and criminology, with which he masked himself - plus, I do believe BK did some peeping and hot prowling. Indeed, if he studied the EARONS case, he would have learned a lot about how to avoid leaving DNA around. He might even have thought that wiping down the sheath with an alcohol or bleach wipe...might have been enough (that's why we always look in the crevices of things for DNA - just as LE took the boot from the seatbelt from the car, and the foot pedals). I am still amazed that the footprint was already latent just yards from where the victims lay dying on the second floor.
IMO. But here's the citation on the mass killing database:
James Alan Fox, Lipman Family Professor of Criminology, Law, and Public Policy at Northeastern University, teamed up with USA TODAY and the Associated Press to launch the Mass Killings database – a public facing website that uses interactive graphics and visuals to break down data on incidences...
cssh.northeastern.edu
I find it instructive, though, to try and get a grasp on the mind of the murderer in this case, by thinking about and studying what we know of the others who are somewhat similar. One big difference between the Idaho murders and Bundy and DeAngelo's murders...is the sexual assault element. I find it plausible that using a knife in the commission of this crime has a sexual element to it, but I think the weapon choice is complex. I think the goal (probably conscious) was to terrorize, outrage, punish "society" (university life/American life/contemporary life) as much as possible. If things had gone the way BK wanted, he would then have climbed into the Catbird Seat and proffered his inwardly gloating, self-satisfied, arrogant opinions on Whodunnit. Which is now one thing he certainly can never do. I bet it rankles him at some level.
IMO, based upon the arrest of BK and the Court's decisions (so far) to move him toward trial.