Ben Aaronovitch & Andrew Cartmel 
Rivers of London [PDF ebook] 
Action At A Distance #2

Thomas Nightingale is a man of immense power, one of the most highly revered magicians in Europe, but with a guarded past. Recently, Detective Constable Peter Grant has uncovered a brief glimpse into his mentor’s history, hidden in the Folly’s archives.In October 1957, Nightingale was reunited with an old friend from the war, Angus Strallen. The pair both survived the conflict, returning to Britain to pursue careers in law enforcement, which led Strallen to London; he was pursuing a serial killer. The man in question was one Professor Uwe Fischer, a Luftwaffe pilot turned boffin at a factory in Strallen’s neck of the woods, Cumberland. Fischer was preying on young women, and Strallen had some evidence to suggest that he was using more than physical power to commit these crimes. He knew of only one man who could help him. It was up to the pair of old friends to work together and apprehend Fischer before he had the chance to strike again.