Aaron Kosminski - David Cohen

David Cohen

Another Polish Jew proposed as a suspect in the Jack the Ripper murders was Aaron Davis Cohen or David Cohen, whose incarceration at Colney Hatch Lunatic Asylum roughly coincided with the end of the murders. He was committed on 12 December 1888, about one month after the murder of Mary Jane Kelly on 9 November. He was described as violently antisocial, exhibited destructive tendencies while at the asylum, and had to be restrained. He was the same age as Kosminski, and died at the asylum in October 1889. Author Martin Fido suggested in his book The Crimes, Detection and Death of Jack the Ripper (1987) that the name "David Cohen" was used by the asylum as a simple name for an inmate whose true name (Kosminski or Kaminsky) was too difficult to spell or easily misunderstood. Fido identified Cohen with "Leather Apron", a Polish Jewish bootmaker blamed for the murders in local gossip, and speculated that Cohen's true identity was Nathan Kaminsky, a bootmaker living in Whitechapel who had been treated at one time for syphilis. Fido was unable to trace Kaminsky after May 1888, and records of Cohen begin that December. Fido suggested that police officials confused the name Kaminsky with Kosminski, resulting in the wrong man coming under suspicion. As with Kosminski, the asylum case notes say he spoke only Yiddish.

The implication is that Kaminsky's syphilis was not cured in May 1888 but in remission, and he began to kill prostitutes as an act of revenge because it had affected his brain. However, Cohen's death certificate makes no mention of syphilis but gives the cause of death as "exhaustion of mania" with phthisis, a then prevalent form of pulmonary tuberculosis, as the secondary cause. Kaminsky might have died as an "unknown" as hundreds of people did each year in the late 19th century. That would account for Fido's inability to find a record of his death in England and Wales during the probable period of his life.

Nigel Cawthorne dismissed Cohen as a likely suspect because in the asylum his assaults were undirected, and his behaviour was wild and uncontrolled, whereas the Ripper seemed to attack specifically and quietly. In contrast, former FBI criminal profiler John Douglas has asserted in his book The Cases That Haunt Us that behavioural clues gathered from the murders all point to a person "known to the police as David Cohen ... or someone very much like him". Using criminal profiling techniques Douglas and Roy Hazlewood concluded that the Whitechapel murderer would have been someone of Kosminski's or Cohen's age, marital status and social class who exhibited erratic or irrational antisocial behaviour and who lived close to the scenes of the murders.

John Pizer was another Polish Jew who worked as a bootmaker in Whitechapel. Police Sergeant William Thicke arrested him on 10 September 1888 on suspicion of being "Leather Apron". Thicke apparently believed that he had committed a string of minor assaults on prostitutes, and he did have a prior conviction for a stabbing offence. The investigating inspector, however, reported that "there is no evidence whatsoever against him", and he was cleared of suspicion when it turned out that he had alibis for two of the murders. He was staying with relatives at the time of one of the murders, and he was talking with a police officer while watching a spectacular fire on the London Docks at the time of another. Pizer successfully obtained monetary compensation from at least one newspaper that had named him as the murderer.