I'll have to pass on David Peace, whose name I had to google.
Briefly, the first problem was that these were random killings in the sense that there was no link eg of the domestic violence type between killer and victims or obvious motive eg robbery. In the early days, I'm not even sure they were linked as a series. Then, the senior investigating officer was deceived by the geordie voice tapes. That's when the closed-mind effect began. Eliminating suspects properly is a bit like turning a key in a lock and looking for a match. Eg, if you know for certain your suspect is a man, women can be eliminated, but in this case, the misplaced faith placed in in the tapes meant that suspects, and specifically Peter Sutcliffe were wrongly eliminated for not having the "right" accent. It's easy to forget that in those days there was no suitable computer system for the vast amounts of information that were being generated and the enquiry was swamped with information in card indexes etc. That served to increase the wish to eliminate suspects quickly. My own - incorrect - pet theory was that it might be a taxi driver, ie somebody who women might largely trust, but I always assumed that if chance had led me to the killer, he'd have been a geordie, because that was what we were told. We were wrongly told that the tapes contained unpublished information about one of the murders but it was eventually found that the info had been in a Manchester paper, where one of the murders had occurred. A change of senior investigating officer came too late. The arrest in South Yorkshire was hardly proficient, in that concealed weapons were not found (apart from anything else, that type of thing can lead to assaults on other officers while the suspect is in custody) and I suspect there was general relief when a reason was found to get Dewsbury to collect him. During the journey back, one of the escorting officers, somebody I know personally like a lot of those involved, sensed that Sutcliffe was a tad more agitated than being arrested for dodgy reg plates might merit and reported his concerns. The detective inspector - who was on the same recruit course as me years earlier - got to the bottom of it all quite quickly. I don't think I'm revealing anything by noting that one of the hard parts was convincing the incident room that the previous eliminations of this suspect had been wrong. IIRC, Among the things to emerge was that the quite realistic image of Sutcliffe given by a surviving victim to a photofit operator was discounted because she described her attacker as having a local accent.
This understandably led to policy changes such as reviews of cases by somebody not involved and investigating officers are always keen to announce they are keeping an open mind.
That's all pretty general and I don't think I've revealed any secrets: I don't actually know any, but if I did, I'd keep quiet.
PS Charlie Peace was before my time
but sometimes the subject of the dreaded canteen humour.
PPS bovlomov: as our own forum undercover person - as shown in your avatar - haven't you any view on the current events being discussed, rather than somebody born when peelers were peelers?