My very FIRST instinct was that this was a bullying case-that one of the girls was killed (bullied, but killed by accident) and they then killed the other one because they were afraid and didn't want a witness. I felt very strongly about the perp being a young person, or even a small group, until they released the picture of BG.
My husband knows nothing about the case. The other day I asked him, "What would you say if I told you that 2 girls were killed at a park, on a local trail, on a day that was meant to be a school day but wasn't?" His first response was, "I'd say it was someone close to their age."
Of course, the image of BG doesn't fit into that.