The Equivoque Principle: Book 1 of the Cornelius Quaint Chronicles

Dr. Marvello's Travelling Circus brings a touch of magic and wonder each time it comes to town, but when a series of gruesome murders coincides with their arrival the performers find themselves caught up in some rather sinister goings on. It falls to ringmaster and master conjuror Cornelius Quaint, ably assisted by his Eskimo valet Butter, to investigate the killings and to clear the name of the circus strongman who is being held on suspicion of murder. But Quaint soon finds that these seemingly random killings are inextricably linked and, what is more, that they all point back to a dark secret in his own past.