N professional instinct said where SP are now searching, under the circumstances N made the call, based perhaps on numerous refusals of SP to do things on her own professional instinct. It's not N fault both investigation parties were sub par that led to where they now are searching so late in the game with both one way or another claiming the credit for it, when N asked for it to be done at the start of the investigation, frankly MIS or SP claiming credit is just salt on a wound for N no doubt.
I don't think anyone in N position who felt things with any police force where not up to par and had the cash to outsource some kind of effort would not do the same, none of us would just stand aside in the same position with professional experience, being ignored by a police force on that would not pay any amount to get information on our child. We all would. No one can fault a parent, esp a woman who carried that child for that. And the crux, where are both parties claiming C now is ? Salt in the wounds.