It really has nothing to do with a missing child, or indeed any other crime.
It is the application of law according to that country. The fact that the application is different to UK is irrelevant - the Court sits in Portugal.
A similar trial set in USA may well have a given a different result to that expected by a UK citizen
The quote is not mine ... it is a quote from the learned judges in explanation of their ruling on Goncalo Amaral's behalf.
It matters not what jurisdiction one would bring such a case to ... there are no guarantees as to outcome ... but in this case very interesting as to the reasoning behind how this particular one was reached.
The interpretation which has been put on the McCann's media appearances by the appeal court judges says rather a lot about them and the thought processes which enabled them to reach their lawful decision.
As we can see ... it is not Holy Writ ... it is their interpretation.
I haven't had time to read any further than that ... but it does give a flavour of things to come.