The murder that I was thinking of in class--that deeply influence Collins, Braddon, and even Dickens was the "Road Hill Murder" (1860) in which a little child was brutally and mysteriously murdered. The ostensible murderer (who confessed), was the 16 year old Constance Kent (1844-1944), though suspicion has fallen on a number of other individuals.  The case was pursued by Jonathan Whicher of Scotland Yard... and the story has been retold in 2008 in Kate Summerscale's The Suspicions of Mr Whicher or The Murder at Road Hill House.  (See: http://tinyurl.com/RoadHillMurder)


Alan