I also lost her then. She was providing input to me for a novel I was going to write, in which there would have been a character roughly based on her. At about the time you lost her, I had told her my publisher needed a release from her to use some of her history she'd shared with me. A simple email with permission would have been enough.
Right after that, she vanished.
FYI - the picture you have is, I'm sure, one she got off the Internet, since it's been used dozens if not hundreds of times elsewhere.
I got many emails from her, and the "sender" was always listed as "Abby," though she only used "Kerri."
Some months ago, a woman named "Abby" poked a novel of mine on Goodreads, giving it 5 stars out of 5. I know that Kerri liked that novel. I thought the picture was similar, though a different girl with darker hair. "Abby" was from Colorado Springs. I think she said, in her profile, that she was 19 - younger than "our" Kerri.
I just published another book, and I was looking at feedback today, and decided I'd send this "Abby" a note. Sadly, she was gone, along with the "like" on my novel.
Anyway, that's what I know. When I was preparing the novel's character, I did get background info on her, and it matches what you said about your Kerri.
That's what I have. If I ever hear anything else, I'll let you know, if you want. Please do the same, if you make contact with her again. I enjoyed my friendship with her.
My best to you,
(Giulia Napoli) - email@example.com