OK. To know that towel was used by Madeleine would make it either Kate or Gerry. So to have Gerry's or Kate's scent on it is not beyond belief. Surely when the dog handlers acquired the towel they took precautions not to add additional scents on it. Still doesn't make sense to be either of the two of them.
The correct way to treat such items is to use tongs to pick them up and then to place them in a plastic bag, which the dogs sniff.
The GNR team performing the search had in its possession, packed in a plastic bag, a towel supposedly used to clean the missing youngster - Madeleine McCann - furnished by her parents.
http://www.mccannpjfiles.co.uk/PJ/INFORMATION-SERVICE.htmSo the correct procedure was at least partly followed. The tracker dogs never seemed to have the princess blanket which was given to the first dog [a patrol dog with some training in tracking].
Nevertheless the tracker dogs followed the same route as the patrol dog. Whether they followed the same scent we don't know, but it's quite a coincidence.
When the patrol dog handlers arrived at 2.30am [his colleague says 1.55am] they entered the apartment
When they arrived at the scene, they entered the McCann's apartment by the front door, and entered the living room, where there were some PJ officers as well as the MCCann couple. The just talked to some colleagues from the PJ and asked for a piece of clothing that Madeleine had worn or used recently. They were given a pink/orange blanket that the child had been covered with in her bed.
http://www.mccannpjfiles.co.uk/PJ/CARLOS-LACAO.htmKate went to get the blanket, so she touched it.
The handler doesn't say he took the blanket away, so it may have been handed back. In theory the blanket should have been saturated with Madeleine's scent above any other scents on there.
If, on the other hand, the two little girls both had these blankets and were both dried with the same towel, we could have the scent of a child who did go to 4G. She didn't, however, have any reason to be on the other side of the road next to block 6.