Lets look at that for a moment. Supposing it is true that the finding of evidence based on a tip that day is what stopped searches and LE statements, try this on for size:
Perhaps the tip that day was not "hey theres a phone laying in the road", but perhaps the tip was more like this: "hey i just saw ______________ (insert name) throwing something out of their car window while driving. i thought it was odd considering the missing persons case."
Perhaps law enforcement knows who put the phone there, or whatever it was that was found that day. Maybe there was a witness to it being discarded, who provided the tip.
If that were the case, who could be the person(s) dumping the evidence that would cause LE to stop searches and stop making statements?
Just my opinions based on a theory I'm working on that perhaps the game changer on that day was not the evidence that was found, but who put it there.