Ben Aaronovitch & Andrew Cartmel 
Rivers of London [PDF ebook] 
Black Mould #3

Peter Grant: policeman, trainee wizard and now pest controller. Joined by fellow officer and Muslim ninja, Sahra Guleed, the two are trying to contain an outbreak of vindictive black mould that seems to be going after the rich and heartless. An all-new and original Rivers of London comic series, written by Ben Aaronovitch and Andrew Cartmel! Set between ‘Foxglove Summer’ and ‘The Hanging Tree’.