This book is about a journalist’s fixation with a particular serial killer, the Golden State Killer. A very prolific offender, he committed 13 murders and more than 50 rapes over about 15 years. Curiously, despite this, he was not especially famous. This journalist, Michelle McNamara, spent a large amount of time with people she met on internet message boards, and with the police, researching the case and trying to solve it, and this is her account of her fixation. In the end, he was not caught by any of this work, but by genealogical DNA. She was important not because she solved it but because she drove interest in it, even giving him the name the Golden State Killer.
Two things struck me about this book, the first being how awful it is that in fact serial murders are completely capable of stopping. This one did. Their crimes are not compulsions, but choices. This makes it much worse. In this case, as the offender was a police officer, they think he stopped when he became aware how powerful DNA was.
The second thing was that the book was not finished by McNamara. She died part way through, in her sleep, from an undiagnosed heart condition mixed with prescription medication. It was sad to see the second author trying to find a way to end the book from her scribbled notes. It reminds you you do not know the day or the hour. In any case, the Golden State Killer was caught a few months later.