Since the 20,000 page dossier on the disappearance of Madeleine McCann has been released by the Portuguese police, it is clear that to describe the investigation as incompetent would be an injustice to incompetent police forces around the world.
The usual method of enquiry by police forces is to ensure that all leads are checked up on quickly and that proper forensic evidence is searched for and used as quickly as possible.
It is also incumbent on police not to ignore lines of enquiry just because they are obsessed with their own theories or are stuck on one particular hunch.
The Portuguese police ignored collecting forensic evidence, they failed to follow up e-mails from the British police who gave them important possible leads based on hi-tech intelligence. They refused to allow the British police to do a mobile phone investigation looking at phone records used in the location until it was too late and they did not even bother to follow up an important lead about a possible sighting in Holland just days after the disappearance.
The truth is the Portuguese Police became obsessed with the idea that it was Maddie's parents or Robert Murat, both accusations that the police files show hold no water at all, that the police failed in their duty to do a proper investigation and look in to all possibilities.
Sadly, it would be convenient for the Portuguese police if Maddie never turned up because it would mask their utter incompetence.