On the serial killer aspect. I'm currently listening to a VI on Colonial Parkway Murders case, Bill Thomas, and the podcast he co-hosts. In the 04 March 2021 episode on a Q&A on those murders he addresses a question on why serial killers supposedly stop. (About 15 minutes into the episode.) He shares what he has learned from LE and profilers. It seems there is shift in the LE, particularly the FBI, away from a SK having a particular type of victim or environment they stalk their victims in. They tend to believe now it is more focused on opportunity. IOW, a SK that might prefer 20 something or 30 something year old females might not walk away from an opportunity with a younger or older victim if it presents itself.
BONUS Colonial Parkway Murders Evidence Listener Questions Answered (Part 2) by Mind Over Murder • A podcast on Anchor
How might affect how I look at this case? IF - and that is a big IF - this is a SK, could his previous victims be women in their residences or runaway/homeless women in the past but coming across two younger victims in a place he found he had an opportunity, might he attack? If the focus is on double child murders like Evansdale or even single murders/abductions of 13-15 yo girls could this be unduly restricting ourselves? By a different set of circumstances, could his so-called 'signatures' be unique to this crime scene and not at his other crime scenes?
Of course, there is a strong possibility this killer hasn't killed before or since. Then again, just because there isn't what is commonly thought of a pattern, doesn't mean there isn't a SK involved. I've got to believe that LE here has searched other cases. But with some errors or omissions in Uniform Crime Reporting, ViCAP system and untested rape kits, his trail might be there. It's just not obvious or available.
Just thinking out loud. Your opinion might vary.