I don't think the alerts brought anything to the investigation, just hints enough to point the finger at the McCann's which Amaral jumped on.
The alert in the bedroom is meaningless, Eddie called back numerous times to finally alert, to what who knows.
The alert behind the sofa, was probably to a speck of blood that Keela also alerted to, yet if Madeleine had been behind the sofa and had bled from a head injury, why just a speck of blood? and why wasn't there any in the grout? Why didn't Eddie alert to a larger area behind the tiles and not just to the exact spot Keela had?
The alerts to the clothes, well were they alerts? Eddie picks the items of clothing up in his mouth something cadaver dogs are trained not to do, so they can't be used as evidence at all. Looking at the alerts it looks as though Eddie is playing a game.
Alert to Cuddle Cat, again Eddie in the first video I saw before it was edited, picked CC up in his mouth and played with it, did not alert to it at all, but then Grime hides it in the cupboard and although Eddie seems to be more interested in what is on top of the kitchen unit than the cupboard and barks, that is seen as an alert to CC.
Alert to the garden, who knows what that was, but it was more than likely to the compost on the soil.
Alert to the car, again to the key fob which had Gerry's blood on it, the other sample taken proved to be from three people even as many as five.
So my conclusion is the alerts mean nothing.