That's a really interesting piece of information. I've been fascinated by this case, initially from afar since first seeing the Disappeared episode, maybe 4 or 5 years ago - and at that time I was of a similar age to both Suzie and Stacy and found myself simultaneously terrified but also intrigued by what could have happened to the women.
It's only quite recently that I am leaning more towards the possibility that perhaps too much focus was put on Suzie's behaviors and mixing with a questionable crowd. I've had a ton of theories, as I'm sure many who stumble upon this case undoubtedly do, but when I think about the circumstances and the timing of the crime, I can't help but think perhaps Sherill, believing that her daughter would be at a friend's place for the night (and would have been out for most the following day), invited someone over to the residence - or was paid a visit, of course completely unaware as to how dark the intentions of this person(s) truly were.
Going back to my earlier post about Stacy's car on the driveway, and from everything I have read about her, she seemed to be quite a low-key individual. Not the most popular girl in school, but a pretty, friendly individual who I think we can conclude probably wasn't running with the wrong crowd for most of high school. And according to her mom, she wasn't hanging out with Suzie that much, or at least not staying over at her place.
So for this crime to work, the circumstances had to be just right. But the timing would appear to align with Sherill (initially) being the main target. Home alone, daughter graduating - and not expected to return that night. The "choice" of graduation night raises so many questions, as do so many aspects of this case, but why did it have to take place that Sunday? And why at their home, of all places. Apologies for the skewed rambling, but I think after some recent processing, I would say I'm beginning to believe this crime started prior to the girls arriving at Delmar Street - and from then, there was no turning back.