The confession was accepted by the court even though Correia's lawyer Marcos Correia objected to it which was his right. The judges undoubtedly heard the tape recording prior to it being played to the court and decided on balance that it was given freely and without coercion. Those are the facts, we are stuck with them, no amount of maybes and if only's can change that situation.
Bottom line is both Leonor and John Cipriano confessed at different stages of the proceedings to this dreadful crime for which they were ultimately found guilty on the evidence. If they were innocent as some claim they had every opportunity to give evidence to the court but they refused. They have nobody to blame but themselves.
Ahh, so you mean the video of the so-called "reconstruction", then?
The defence did object (Marcos Aragão wasn't even on the scene at that point, AFAIK, so I'm not sure where that idea came from), on the grounds that it constituted a "confession" and shouldn't have been admissible as the defendants didn't take the stand. The court ruled that it was a different form of evidence and was therefore admissible.
What no one seems to have questioned is the circumstances leading up to this "reconstruction". João has stated that he was threatened with being stabbed and was frequently beaten. That may or may not be true. He may, after all, have been offered coffee and cupcakes by the same PJ.
Without CCTV evidence of "interviews", it's one person's word against the venerable PJ.
On the other side, there was no evidence that he'd had to be taken to hospital due to an excess of "coffee and cupcakes", but then neither can I find any evidence that the defence ever tried to found out.