I was saying this to my wife earlier.
First thing any normal person would do is expect the owner to be closeby when a dog runs over. Then my concern wouldnt be to take it to a school, it would be to hold onto the dog and maybe go on facebook and post in our local facebook group Ive found a missing dog.
Even if this happened - if someone rang me to say my dog had been found, I would say that my wife is walking the same route we always do, just go hang around at X place, or go find her here. I wouldnt call the police immediately - I wouldnt even do that until Ive driven down there myself and had a look. I know my wife would be absolutely furious if I just called the police and she was just stood talking to a friend and not realised the dog had gone missing. All I would of thought is that shes out there also looking for the dog as this dudes taken it to the school, or taken it in.
The timeframe it was from her last being spotted to finding the phone just seems completely strange the events that happened. Him calling 999 so fast also makes me think he knew something we are not being told - like suicidal, or hes recieved a message or something.