Here we have the final novel in Peter May’s Enzo Macleod mystery series. Years ago, Enzo, a forensic scientist, made a bet that he could solve a series of famous French cold cases described in a book written by a friend. Two cases are left, but they’ll both be unraveled by the end of Cast Iron.

In 1989, 20-year-old Lucie Martin was murdered, her body hidden in a lake. In 2003, due to a drought, the body was uncovered and examined. The skeleton had a broken hyoid bone, a sign of strangulation. Suspicion settled on a pimp named Regis Blanc, who had been convicted of strangling three prostitutes, and who had been dating Lucie. But he had a “cast iron” alibi.

In 2011, Enzo Macleod turns his attention to the Lucie Martin case. He thinks there’s more to the matter than earlier investigators guessed. And – intriguingly – he discovers a link to a previous murder he solved, though he wasn’t able to identify the person who paid for that murder for hire. This he will learn in Cast Iron. And clearly he’s getting too close to the truth for somebody, because a threat of violence is directed at someone near and dear to him.

As I mentioned in my last review, Enzo has grown in character through the series. I still don’t entirely like him, and I don’t think he’s ever really taken responsibility for some of his sins against others. But he’s better than he was, and this book brings the series to a satisfying conclusion. Three narrative threads are actually tied up at the end. Two I saw coming, but one came right out of left field and was an entertaining surprise.

Recommended, with cautions for language and mature themes.