I dunno, I think that receipt being found where they were searching made them want to know WHY it was there, and who left it. Luckily they were able to track that lead down, and see that it wasn't anything involving the case.
I just can't get a feel for this case. I posted in another case how sometimes you read the first few media reports and just get 'that feeling' of what might have happened. Not getting much here, other than I do believe she was either followed home, someone was waiting for her at the home, and possible someone she knows, but maybe not closely knows. That's about as far as I get before I get to the "I have no clue!" phase.
Unless there was a note left saying she ran away, which I don't feel there was, then there was evidence of 'something' at the home that just wasn't right. As to if Mom called friends before police, hard to say. If the phone was there, maybe. However, if the phone wasn't there, then Mom might not have a clue to what numbers to call! And kids change those phone numbers so much that even if she had numbers, doesn't mean they were still active. I know I could call a few of my daughter's friends from the phone book, and call their home phone, but as for the cell numbers, I can't keep up with them! So if my daughter's phone was gone, there would be only a few I could call up, though I know where they live!