The surviving police files on the Whitechapel murders allow a detailed view of investigative procedure in the Victorian era. A large team of policemen conducted house-to-house inquiries throughout Whitechapel. Forensic material was collected and examined. Suspects were identified, traced and either examined more closely or eliminated from the inquiry. Police work follows the same pattern today. Over 2000 people were interviewed, "upwards of 300" people were investigated, and 80 people were detained.
The investigation was initially conducted by the Metropolitan Police Whitechapel (H) Division Criminal Investigation Department (CID) headed by Detective Inspector Edmund Reid. After the murder of Nichols, Detective Inspectors Frederick Abberline, Henry Moore, and Walter Andrews were sent from Central Office at Scotland Yard to assist. After the Eddowes murder, which occurred within the City of London, the City Police under Detective Inspector James McWilliam were involved. However, overall direction of the murder enquiries was hampered by the fact that the newly appointed head of the CID, Robert Anderson, was on leave in Switzerland between 7 September and 6 October, during the time Chapman, Stride and Eddowes were killed. This prompted the Metropolitan Police Commissioner, Sir Charles Warren, to appoint Chief Inspector Donald Swanson to coordinate the enquiry from Scotland Yard.