Yes it's terrible, and serious clinical errors and misjudgements were made that need to be explained. But I am not sure how the police can be blamed. They were called in a long time (in investigation terms) afterwards, and on what appeared to be an entirely unconnected matter. Post-mortems are not generally carried out 18 days after death, so it would seem that it was actually the thoroughness of the police investigations into allegations of mistreatment and neglect made several days afterwards that this death even came to light. By that time all possible evidence had gone. It doesn't matter how long you investigate something. If there is no evidence, then there is no evidence. I suspect that the unusually long delay in the coroners court was due to them turning over every stone they could, for several years, before coming to the conclusion they could not proceed any further.
Almost certain he will attack again. Without being indelicate and bearing in mind the (no doubt underplayed) horrific description of the injuries, there is no certainty that this was a man or a member of staff. Outrage is absolutely justified, but you cannot suspend people "until they speak the truth" when you have no evidence that they are lying.
What I would like to hear about is the wider context, because there was certainly something seriously awry in that ward and again, justified as the outrage is, the risk is that that fact gets lost.