I'm a bit concerned that this has been an active case for quite a while now, yet they still haven't re-examined the CCTV, or digitised the case files. The lack of digitisation is weird. It's not like computers weren't around during the initial enquiry.
At least POIs are being reviewed, but I think it's a mistake to presume the killer is in the case files. Christopher Hampton wasn't in the case files for Melanie Road, despite living right there in Bath.
I also wouldn't rely too much on the police using AI, although I hope I'm proved wrong. When the police used cutting edge technology in Operation Enigma, the results turned out to be underwhelming.
I completely agree
AI is not something that can be relied upon, because it will inevitably amalgamate multiple cases into one.
This has already happened with the incorporation of AI in some of the more historical cold cases from the Victorian era.
AI will no doubt be excellent in some areas, but it can never replace that gut instinct that is essential for every case.
The irony will be that AI will learn to mimic "human error" and that will be catastrophic in terms of then being able to then prove that the AI was wrong.
I also agree that it feels wrong to automatically assume that the killer is already in the case files, because as you rightly say; the man who killed Melanie Road in Bath wasn't in the case files.
The idea that the police believe that the man who killed Melanie Hall is in the case files; combined with her family eluding to the idea that they believe someone knows more than they're letting on, would then suggest that the police likely know who the culprit was, but because of the lack of sufficient evidence, the police can't take it any further until another source comes forward, or they have something more concrete to go on.
After all, it's not about what the police know, it's about what they can prove.
That's more frustrating in a way, because while their belief that the killer is in the case files does help to narrow down the suspect pool, it also significantly hinders the case ever moving forward to a favourable outcome, because there's a likelihood that the killer is someone they've never considered before.
If the police had applied that same logic to the Melanie Road case, they would never have caught their man in Christopher Hampton.