I am not able to read all posts every day so my apologies if this has already been covered, but two things keep coming to mind:
*I keep thinking about the “who” – more often than not, it is someone who has some knowledge of the child. (think April Jones – MB knew her family & she was not afraid of him). He had never murdered a child before (as far as can be determined), but was set off because of a breakup with his girlfriend.
*Once the child is dead, most perps want to be ‘rid’ of them (quickest way possible – usually not a lot of pre-planning, although a lot of time may be involved in the disposal). Since the window is SO small, this person must have still been really close to the area right afterwards. Did someone miss work that day or night? Or were they late with a lame excuse? Were they edgy? Preoccupied with the news or didn’t want to hear it at all? Someone saw them whether they realize it or not. Someone’s behavior changed THAT day or has changed since, almost without question.
If LE and/or the parents keep this case in front of the people who live in that immediate area it may help jog a memory, or nudge someone who already has concerns to come forward. That is one way that cold cases get cracked – family & investigators keep reviewing the info and asking questions of people they have already talked to until they get a break. If everyone is quiet, people’s consciences go numb & they can think about other things.
LE in Wales scoured the countryside for months looking for April. We know where Alanna is, but what good is that without knowing who did this to her, getting justice for her & taking this vermin off the street?