You mentioned the case of Shannon Matthews in one of your posts. This is what The Nat Policing Agency said in a review of the case which included the use of Victim Recovery Dogs:
"The properties that the dog searched contained a high level of second-hand furniture bought from dwellings where someone had died. This resulted in numerous indications that required further investigation to confirm whether they were connected to the investigation, or to previous owners of the furniture."
5A didn't belong to the McCann's. They simply rented if for 7 nights. How would anyone know the history of the place in terms of materials used in construction, construction workers, fixtures and fittings, furniture and human traffic any of which may have come into contact with a corpse directly or indirectly and then caused the dog to alert?
The only owner occupier in the block was Mrs Fenn situated directly above 5A. Prior to purchasing her apt at OC she lived elsewhere in Portugal with her husband who suffered Alzheimer's. Upon his demise she purchased the apt. Is it possible the dog alerts were connected to Mrs Fenn's apt?
Re the hire car were the control cars like for like ie hired or similar? If the control cars sustained far fewer drivers/passengers then there's less likelihood of them coming into contact directly or indirectly with a corpse. For all we know the hire car might have been rented by an undertaker. What checks if any were carried out on the cars to determine their history?
Afaik the substance thought to be blood as evidenced by the dog alert wasn't visible to the naked eye? LCN DNA tests were inconclusive. Therefore it seems to me if the substance was blood the potential sources are many and varied: people cut themselves shaving or on sharp implements, children have bangs and scrapes, women have periods, etc, etc.
I'm not a McCann supporter just looking at reasonable explanations for the alerts other than something sinister.
Do we know if Mrs Fenn’s husband died in hospital and if so why would she have taken anything he had with him at the time to her new apartment?
I asked you on the ‘smells’ thread but I don’t think you answered. Why did the dog not alert to any of the tapas group’s apartments or belongings ? Each couple included a medic and their apartments were all rentals, facts you think may have been significant.