A compact thriller (167 p. of relatively small type), this story proceeds in alternating chapters, one set featuring an odd couple pair of cops (younger female with a drinking and wild-catting problem; elderly disillusioned Scot - Inspector Munro - who is her supervisor and superior in detective skills.) Munro has a dark secret in his own past, and it comes back indirectly to bite him in this case. The other half of the chapters are first-person essays, apparently in response to some sort of interview questions; the identity of the speaker/writer only gradually becomes apparent. As the only living character in the book with extensive knowledge of the serial killer, his narrative gives us the inside view of her (yes, it's a woman). The case wraps up very strongly with all sorts of loose ends and motivations accounted for, so I found the attempt at a "twist" ending in the epilogue actually rather weak - I didn't buy it at all.
Some of the gruesome details of the murders (she's a would-be anatomist/coroner if that suggests anything) would likely prove quite upsetting to a sensitive reader. I hesitated myself after a couple of chapters but was glad I persisted.
I am not thrilled with the character of the junior detective (D.S. West) at the moment, nor am I a fan of Munro's dismissive attitude to her. Possibly this improves in the sequels.