Guessing, but if someone has badly ricked up the child protection side of the scenario, it needs to be investigated by a body not connected to the ones who made the ricks.
Identifying the body - possibly, as it seems she was in some kind of bag (?large sports bag?) and left in a warm loft for a week of warm weather, this will be a challenging thing for pathology to prepare for viewing, and for a traumatised relative to view.
DNA - yes, straightforward, expensive, takes time. They possibly are awaiting results as we write.