I don't know anything about the police dogs, in all their different fields, but if the Police did send in sniffer dogs or tracker dogs on the first dog visit to the house, then surely if Tia had been staying there, then her scent would be expected to be in most areas of the house wouldn't it?
I would guess that maybe the dogs were there originally to find a scent and then track it to another location as the Police always seemed to be intent on the theory that Tia was somewhere local.
So maybe it was only when the last search with what is rumoured to be a cadaver dog was done, that it alerted to wherever the body was.
I personally cannot believe that if the body was placed in the loft, that the previous searches would not have uncovered it, ( bear in mind, these houses are no more than 15 to 20 feet wide and less than 30 feet deep), I really hope for the sake of the Police, that she was somewhere that would have been difficult to locate and that is why she was missed.
As much as I want to have faith in our UK police force, the more I see, the worse we seem to get, (Don't have much hope for all the Police reviews that are being carried out).
If we all had suspicions of Stuart Hazell, then there is no doubt the Police did, so unless they purposely allowed him to wander, last night, then they really do have a job on their hands in convincing the public of the competence in their handling of this case.