The killer could have definitely had sexual gratification even though there was not an actual assault. Also, based on the requirement of sheer strength and endurance it would require to stab through bones/breastplates while potentially fighting 4 different victims leads me to thoroughly believe this is a male subject.
As I’ve said since the beginning, I think this was a “Thrill-Kill” which is a psychological serial killer subtype. Thrill killers have a specific MO and reason for their crimes and are usually so random, they’re extremely difficult to catch: Think Isreal Keyes or the Night Stalker, Ramirez.
More on thrill killers here:
What are the different types of serial killers? - Psychology of Psychopaths 2a
There is a term criminologists used called piquerism : “Piquerism is a sexual interest in penetrating the skin of another person with sharp objects. Sometimes, this is serious enough to cause extreme injuries or even death. Piquerism is a paraphilia as well as a form of sadism. The most frequently targeted areas of the body are the breasts, buttocks, and groin.”
Wikipedia
The most famous case of this was Jack the Ripper, but I think there was more of a physical actual sexual assault component but not with every victim IIRC.
Rollings and Bundy both obviously went into houses filled with women and committed murders but there was obvious signs of SA.
Here is a screenshot of the first page of a Case Study of piquerism that is very interesting.
View attachment 382194
All of this information is something to think about considering there are 2 behavioral units from the FBI and no suspects/POI’s right now: It seems they’re concerned with what they saw.