Answer:
One source that could be useful for an historian investigating the difficulties faced by historians policing Whitechapel is the official reports and documents related to the police investigation of the Jack the Ripper murders. These reports and documents could provide valuable insights into the challenges faced by the police during the investigation, such as the lack of forensic technology and the difficulties in gathering evidence from the crime scenes.
Additionally, contemporary newspaper articles and accounts written by journalists who covered the Jack the Ripper case could also be useful. These sources could shed light on the public perception of the police investigation and any criticisms or controversies surrounding the police's handling of the case.
Overall, official police reports and contemporary newspaper articles could provide valuable perspectives on the challenges faced by historians policing Whitechapel, as they offer firsthand accounts and insights from the time period in question.