You and I and WS'ers understand what you are saying. But a family thrown into a nightmare like this doesn't realize that keeping up appearances hides the truth, and the truth is what will lead to the victim being found and justice being served. They really just do not know any better. JMO.
IMO they also don't know if she might walk in the door tomorrow and want to continue on with life, so I can see why they'd conceal things from the public if that's what's going on.