Injections of Insanity (DI Sterling Book 3) - Lorraine Mace

Detective Inspector Paolo Sterling has just six weeks to solve a series of murders by insulin injection, with nothing to connect the victims except the manner of death and a note left at each crime scene. The murderer, determined to avenge a wrong from many years earlier, gets close to his prey by assuming various identities. Can Paolo win in his race against the pretender?