The King's Justice by Susan Elia MacNeal

A serial killer is on the loose in wartime London, and the press have nicknamed him "Jimmy Greenteeth." The police are eager to have Maggie Hope help them with the case, since she was instrumental in putting the murderer Nicholas Reitter behind bars. Maggie wants no part in it and spends her free time drinking excessively, while being part of the official group that defuses Nazi bombs around London. However, as Jimmy Greenteeth claims more victims around the capital, Maggie is drawn into a web of murder yet again.