So who was this abductor ferryman ?
The invisible man perhaps ? 
... when I entered to PJ, young, in 1981, with 22 years old, we wanted what today I don´t know if it will be much, to investigate homicides, to investigate drug trafficking, investigate organized crime, and we were with, shall we say, adrenaline, the areas of children, of the missing children or adults, was always mistreated areas, and I remember the father of a missing youngster from Porto, here, Jorge Sepúlveda, which told that in 1991, when he presented, when he told about his son´s disappearance, that there was only one inspector to investigate the disappearances and ten for car theft, the car is much more important than a child, this continues, and that case made me awake for that reality, the reality of the families, those families whose sons disappears, what is the state, the organizations, the police itself, how can help them, what they can expect from police forces, what the police forces can expect of an absence long term, this is nothing, this means nothing, there isn't a planning in terms of investigation, and people are adrift.
Host: This case did not change a thing in Portugal?
GA: Did not, did not, but I hope that it will, because, this is the problem of PJ, and as a superior organ of criminal police, it should have that attention.
The PJ has a legal obligation, because it is at PJ´s organic law, to detect criminal phenomenon, and that doesn´t happen, the PJ continues to react (like any other police) to a real event, then no studies about the phenomenon, and PJ don´t prepare in this situation, the disappearances of children, or an adult disappearance, people who, people don´t even know where to complain, there is an informative note that PJ at 2007 which says something like this: by the way of the missing children´s day, well, don´t forget to give useful advices to parents of missing, half a dozen, but don´t forget that this not crime, and that it is at that informative note, it´s no crime, it´s not investigated as a crime, there is no urgency (for people to understand)
but it has to be investigated as a crime, because a child who disappears, everything may happened, a crime, and if not investigated.many things will be lost (12:19).
https://www.youtube.com/watch?v=LMwAsA3bgY4&feature=player_embedded#Mr Amaral seems to have been aware that all the stops have to be pulled out when a child goes missing. The result of any failure in the investigation means ... "many things will be lost".
He appears to be of the opinion that all avenues of investigation have to remain open ... in particular that the disappearance of a child has to be treated as a crime.
To reiterate that 'the nature of the crime is unknown' is semantics ... when you are aware that the current Policia Judiciaria and Scotland Yard investigations are concentrating on abduction.
Not because they have been told to ... but because they have been following the evidence from scoping exercise to review to reopening of the case.