It is now 2017 and Goncalo Amaral talks freely about the case. He's no longer shackled by profession or court cases by the McCanns.
He opens up and reveals many previously unknown details about the investigation. He says the Mccann's were protected by diplomacy but won't go further than saying the cause for that protection was simply their social status. I'm reading "something else might be in stake there, like a sex ring, but I don't have solid evidence of that".
Goncalo talks about David Payne, whom he addresses as the "true mistery man" in this case. He's very suspicious of his actions that night and of his devious sexual nature - atested by the statements given and his own actions.
Goncalo Amaral is clear about the investigation being cut short. The accidental death scenario is his best account of what happened that night, however. he was retired from the case. He's clear that the true investigation, with the parents being the main suspects, never happened. The powers that be wouldn't allow it.
He doesn't absolutely rule out the possibility of a homicide nor does he rule out the possibility of devious sexual behaviour taking place between adults and children. Unfortunately, he wasn't allowed to investigate into those possibilities.
RIP, Maddie.