Can anyone prove that Amaral sat down to write a book with the deliberate intention of deceiving people? Can anyone even explain how he hoped to get away with that when the book described the investigative process in which many other officers were involved? Or were they all complicit too? Has a conspiracy been uncovered? 
IMO he deliberately led his readers to believe they were reading a first hand account from the policeman who had been face to face with the McCanns. interviewing them and observing them - when in reality it was only a secondhand account because he had never met or spoken to Kate McCann in his life - and had only once briefly met Gerry when he wrote his book
It's pretty obvious that an account straight from the horses mouth would be of far more interest to potential buyers than a book that was a compilation of the accounts and impression of others.
There was nothing in his book to give his readers even the tiniest hint that that was the truth of the matter - in fact mainly by the copious use of the word 'WE' - the opposite impression is given throughout - and even when asked directly in interviews not once did he ever admit the truth. Why try to hide that fact if there was nothing wrong with it.
If I had bought his book and then found out after reading it that he'd never personally met or spoken to the McCanns - I would certainly have felt that I had been deceived. Wouldn't anyone?