During the Jack the Ripper murders of 1888 they were led by Chief Inspector Smith. Catherine Eddowes was murdered on Whitechapel High Street, a City of London land but evidence tied to the case was on Goulsten Street, a Metropolitan land. This meant that Lewis couldn't help Amy Pond with stopping the murder until he had gotten permission from a local policeman and Chief Inspector Smith was unable to stop "Sir Charles Warren" from having the Goulsten Street message removed. Finding the Eleventh Doctor kneeling over a paralysed Amy near Eddowes' body, the city police arrested him as the Ripper.
Warren wanted the members of "CSI London" removed from the Elizabeth Stride murder scene when told that they were probably with the city police. Rory Williams later claimed this group was created to work with both police forces. This allowed him to bring Frederick Abberline to the murder scene of Eddowes and ended up making him the head of the Ripper task force when trying to stop a sixth and seventh murder from occurring. According to the Doctor, the death of the fifth canonical Ripper victim (Mary Warner / Mary Kelly) led the two police forces to acknowledge their mistakes and begin working together. (COMIC: Ripper's Curse)