I've never tried to read the 87th precinct books in order, and I only read them sporadically so I'm not sure if the detectives do age or change in situation as the series goes on. Certainly things always seem to be much the same in the squad room to me. This book was written in 1972 and struck me as aged more than many books do. Carella refers to serving in World War II and the descriptions of electronic surveillance devices and the introduction of direct dial telephones seem to set this book back in pre-history more than I've noticed before in other episodes in this series.
In only 160 pages this is more of a novella than a novel and the plot is strangely transparent. I'm wondering if I missed something because it seemed obvious to me what happened both to "Sadie when she died" and how the case was going to be solved. No real surprises for a mystery and especially disappointing for a mystery that is featured on a 100 favourite mysteries of the 20th century list.