Law Enforcement seems to be somewhat sketchy about how this search originated. It sounds to me like the family chose a specific location for some reason and hired or initiated getting the sonar people to do the search. Yet law enforcement didn't seem to want to just say that, but rather keep repeating "we've been working with outside groups throughout the investigation". We get that, however, the question is obviously in regards to why that specific area was to be searched today. I trust it wasn't random.
Maybe we are all ignorant and these sonar guys searched 8 miles of river before they found these cars. However, it sure seems like they came right to the spot where the cars were found. That part makes it seem like **someone** suggested a location.
Maybe the source of this mysterious parkville ping that LE didn't even tell us about or confirm, is the single most important piece in the whole case and is all that was needed to find her. ya know? So can someone just tell us, where that ping information came from???