Actually, we don't know much about the facts of the killing and nothing about the circumstances leading up to it. Even events afterwards are sketchy. I think it is a little disturbing that people are so willing to consign this child to the deep knowing so little about the case itself.
OPINION...........
I think people are willing to believe that Alyssa killed Elizabeth. A Grand Jury is certainly willing to believe it. Local Law Enforcement is willing to believe it as well.
Why? Well, Alyssa SAID she did it. Then she led them to the well-concealed dead body of a strangled 9 yr old with a slashed throat and stab wounds. Pretty good reason.
You're completely correct that we know very little about the killing or the circumstances leading up to it, or events following. We have had to pick and poke through the miniscule amount of information made public, listen carefully to the tone of voice of those who've spoken publicly, examine the looks on their faces. And I can tell you, we're afraid that the reason they've only shown us the tip of this iceberg may be because the rest of it is even more gruesome, or frightening.
St. Martins is a small town. Jefferson City is a small town. We're a rural area with a pretty low crime rate, especially when it comes to murder. Sure, there have been domestic murders, drug deals gone bad, robberies that end in murder, stuff like that over the years, which are bad enough, but up to now, our children have not really been threatened. This one hits hard, right in the gut. DO NOT HARM OUR CHILDREN. Everyone across the country is reacting from that emotional punch to the gut, and on top of that is the shock factor of the "bad guy" being a cute little 15 yr old girl.
EVERYONE isn't willing to consign her to the deep, as you say. Some are, some aren't. Nearly everyone wants to be sure that she isn't returned to society until and unless she's paid a significant price for taking a life, AND rehabilitated to the point that she no longer poses a threat to our children. I expect that'll take a while. Isn't it true that young murderers do often see freedom, and often at an age where they can have a family and a life after prison? If Alyssa is mentally stable enough to be released at age 30 or 35, she can still have a full life. Elizabeth can't.