Except we are now being told the other deaths and collapses weren't sudden so weren't suspicious. So why did Evans believe they should be investigated?
If the criteria were, not easy to find an opportunity for Letby to have murdered these children, that sets up the statistical fallacy we have been discussing.
If the criteria were, too sudden to have been a natural death, what was the difference between these cases and those tried, and why are they now not described as sudden.
I mean, none of us know the answer to exactly what criteria was applied at what point and all the details of the discussions and reports between the police, CPS, Evans, etc so any suggestion would be mere speculation. The police have released a YouTube video of how they conducted operation hummingbird, though, so that might help to shed some light on their strategy.
I do think that given that Evan's was instructed by the police as opposed to by the hospital, it's reasonable to assume that weighing up the prospects of conviction against the cost of further investigation on each individual medical case probably was a consideration in the work Evans was instructed to carry out, though.
So it seems plausible that there were cases where Evans might have been told "you can drop that one for the moment" regardless of the circumstances simply because the priority was on building a credible case to take to the CPS at that point. There was a huge number of documents to go through so it makes sense that certain cases and evidence would be prioritised for the specific task at hand.