Yes.On one hand I agree.. I was amazed he was allowed to search alone. But I can also see that it might have been their only chance to discover the truth. They have time constraints and only he could reveal the body. We also don’t know that they didn’t have some way of keeping an eye on him. Hmmmm.. all very puzzling.
The other thing is that although he has been interviewed 3 times it is apparently by 3 different Police forces (Spanish/French/British). I don't know how they operate but I would have thought if he was a genuine suspect they would have brought him in again for follow-up questions just to see how he would react to that - but I admit that this is just specualtion on my part.