Authorities believed Druitt was the Ripper

The argument

The case for Montague John Druitt does not rest on modern reconstruction but on what the people closest to the investigation believed at the time. The most senior of them was Assistant Chief Constable Sir Melville Macnaghten, one of the top investigators in the Ripper case, who named Druitt as a suspect in a private memorandum on February 23, 1894. The setting matters: a private memorandum is not a public accusation made to satisfy pressure for an arrest, and a name recorded internally rather than announced is more likely to reflect what the investigator actually thought. Following his retirement in 1913, Macnaghten went further, claiming to know the exact identity of Jack the Ripper on the basis of private information obtained from the Ripper's family. He was referring to Druitt. Information from a suspect's own family is the sort that cannot be assembled from the crime scenes, and it is not what a retired officer has any professional incentive to invent. The second strand is corroboration from outside the police. Comments by Henry Richard Farquharson, MP for West Dorset, and by others including journalists and public officials from the Ripper's era, indicated that the Ripper was the son of a surgeon and had committed suicide at the end of 1888. That description was circulating among people with no evident connection to Macnaghten's memorandum, and it is specific rather than generic — a profession, a family position, a manner of death and a date. Druitt matches it on every point. He was the son of a local Dorset surgeon, and he committed suicide in December of 1888. Where the senior investigator's private conclusion and the independent contemporary description converge on one man, the inference drawn here is that the authorities of the day believed Druitt was the Ripper, and believed it on grounds they considered sufficient.

Premises

Counter-arguments

Official suspicion is not proof, and Macnaghten's case is weak on its own terms. He wrote his memorandum years after the murders, named Druitt only as one of three possible suspects, and conceded the information was private and unprovable — while getting basic facts about Druitt wrong, including his profession. The contemporary rumour of a surgeon's son who killed himself was hearsay circulating after the fact, not evidence tying Druitt to any crime scene. That a retired official believed something decades later, without producing the family information he claimed, cannot establish identity.

Rejecting the premises

[Rejecting P1] Macnaghten named Druitt only as one of several suspects, wrote long after the events, admitted the evidence was private and unprovable, and made factual errors about him. [Rejecting P2] A general rumour of a surgeon's son who committed suicide is hearsay that fits many people and ties Druitt to no actual evidence.