I think the very professional job carried out by the GNR dogs and their handlers has been underestimated as they were pushing what they had been trained to do over and above the limit ... I don't think it was rocket science to realise that VRDs were required to follow through on their responses.
That would perhaps have saved a lot of future distress and misunderstanding.
The search and rescue dogs. brought in on 4th May; took this route;
At about 23.00 the extra teams that had been requested for reinforcement arrived (Officer Rosa with Oscar and Officer Martins with Fusco, both from the search and rescue unit and Officer Fernandes with Rex and Zarus from the tracking team).
After the officers had been updated about facts relating to the disappearance, they tried to reconstruct the route the girl might have taken with the two tracker dogs. For this purpose the dogs were given a blanket to sniff, provided by the parents, which had been used by Madeleine.
Beginning to follow the track using Rex, from the door of apartment 5 A (the place where the girl had been sleeping) he would always head in the direction of Block 4, leaving block 5 the dog would turn to the left, pass by a metal access door to a path existing between the apartments blocks to the leisure area (restaurant, pool and playground). Immediately another attempt at reconstruction was made using the dog Zarus, who, in general terms, ended up following the same route as Rex and having the same behaviour.
They returned on 7th May;
At about 23.00 accompanied by a PJ inspector, the searches were begun. After Rex was given the girl's clothing to sniff, he began to search on the ground floor of block 5 and when he passed the door of apartment 5 A (the place the girl had disappeared from) according to his handler, officer Fernandes, the dog altered its behaviour, sniffing with greater intensity than he had done before. Apartment 5J of the same block was also checked as the dog had been more agitated than before as if there were a very strong strange odour there. It was stated that this apartment had been unoccupied for some time. Afterwards, the same kind of search was carried out using the dog Zarus which in general terms showed the same behaviour in the same places as Rex had done.
http://www.mccannpjfiles.co.uk/PJ/GNR_SNIFFER.htm