What I fail to understand is, to get cadaver odour in the first place a body has to be left for an hour and a half.
So, if Eddie alerted to cadaver odour behind the sofa [I believe he alerted to blood] then Madeleine would have had to have been there for about an hour and a half. So when would this have happened?
If Eddie alerted to blood
and Madeleine bled on or before 3 may 2007
and Eddie alerted on ... whatever - months later
would the blood have been dead enough for Eddie to alert?
Now, if we were sure that Eddie alerted only to dead bodies, as opposed to dead blood, then Eddie's alerts would be interesting.
If the substance Eddie alerted to was Madeleine's blood, then given the long time that had elapsed since Madeleine disappeared before Eddie searched, I would be really worried by non-dead blood. That would be into the Madeleine-was-an-alien bucket.
Dead blood tells us nothing about how long a potentially dead Madeleine was behind the couch.