Well well, after getting caught up on the days activity, just a few thoughts.
Still no charges and we are about 45 hours now (I believe arrest was 6am). And they would have planned the time of arrest in order to maximize interviewing time. I suspect NUA would have finished the second long and grueling day of answering the same questions over and over.
Witnesses, confessions, and forensic evidence. I recall a retired detective early on in this case saying no one is ever convicted without 2 of the 3. At this point regardless of who did it you got to say things are not looking good. No witnesses of any sort. Will a confession come? Doesn't seem likely. And they certainly do not seem to have much forensic evidence, but even if they do is it enough that it will hold up without the other two? It would have to be some very solid evidence, like a ring at the flat on Aberdeen or something of the like.
If NUA did do it, it is hard to believe it took 5 weeks to get where we are. It always struck me as very unlikely something could have occurred in JY's flat without an immediate neighbor hearing something. One would think the flat next would have been subject to the same scrutiny the one above was in the same time frame. Also, LE said in the days after JY was found that they were exclusively focused on the UK and that they had no concerns the perp had gone abroad. Looking back that almost seems designed as a message that NUA was not a suspect at the time, and designed to keep the focus off him. Why were they so sure then that NUA wasn't involved? What has changed?
Where was NUA's GF in the time frame 12/17-20? If she was not at Canyge and LE knew that from day 1, hard to believe NUA wouldn't go right up the list as possible suspects along with the other 3-4.
Where was NUA from 12/20-25? It's said he was in Holland but that doesn't appear to have been corroborated.