Blacklight Blue - Peter May

Enzo MacLeod, a Scot teaching on a faculty at Cahors in south-west France, confidently bet that he could use his expertise to crack seven notorious murders described in a book on cold cases by Parisian journalist Roger Raffin.

Enzo has in fact solved the first two crimes. But the third is far from his mind right now: he's just been diagnosed with a terminal illness, and he's become the victim of someone who seems intent on destroying his credit and his relationships - and getting him arrested for murder.

This is one instance where his Scottish stubbornness might pay off. Having established a safe house to protect his loved ones, besieged now as it were, he sets to work. Are his personal woes somehow connected to the digging he's done into the brutal murder of a rent boy in a Paris apartment sixteen years ago, as Raffin has described? What further remnants of evidence can he review - and can he stay alive long enough to catch the long-hidden killer?