Aaron Kosminski

In September 2014, author Russell Edwards claimed in the book Naming Jack the Ripper to have proved Kosminski's guilt. In 2007 he bought a shawl which he believed to have been left at a murder scene and gave it to biochemist Jari Louhelainen to test for DNA. A peer-reviewed article on the DNA analysis was published in the Journal of Forensic Sciences in 2019. However, scientists from Innsbruck Medical University have criticised the paper and its conclusions, pointing to a number of mistakes and assumptions made by its authors.

Former City of London Police officer and crime historian Donald Rumbelow criticised the claim that the evidence proved Kosminski was Jack the Ripper, saying that no shawl is listed among Eddowes's effects by the police. Mitochondrial DNA expert Peter Gill said the shawl "is of dubious origin and has been handled by several people who could have shared that mitochondrial DNA profile". The shawl or other material could have been contaminated before or while DNA was being tested; two of Eddowes's descendants are known to have been in the same room as the shawl for three days in 2007, and, in the words of one critic, "The shawl has been openly handled by loads of people and been touched, breathed on, spat upon". Despite the criticisms, Louhelainen continued to defend his work.

In his book Naming Jack The Ripper, Edwards names Kosminski as Jack the Ripper. Edwards was inspired to try to solve the case after the release of From Hell, the 2001 Johnny Depp film about the Whitechapel murders. He bought the shawl at auction and commissioned Louhelainen, with Dr. David Miller assisting, to analyse it for forensic DNA evidence. Edwards states that Kosminski was on a list of police suspects but there was never enough evidence to bring him to trial at the time. Kosminski died at the age of 53 of gangrene of the leg in a London mental hospital in 1919. He said that the DNA samples proved that Kosminski was "definitely, categorically and absolutely" the person responsible for the Whitechapel murders committed by Jack the Ripper. "I've got the only piece of forensic evidence in the whole history of the case," he told The Independent. He continued, "I've spent 14 years working on it, and we have definitively solved the mystery of who Jack the Ripper was. Only non-believers that want to perpetuate the myth will doubt. This is it now—we have unmasked him".

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 said in his 2000 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".

In 1987, Ripper author Martin Fido searched asylum records for any inmates called Kosminski, and found only one: Aaron Kosminski. At the time of the murders, Aaron apparently lived either on Providence Street or Greenfield Street, both of which addresses are close to the sites of the murders. The addresses given in the asylum records are in Mile End Old Town, just on the edge of Whitechapel. The description of Aaron Kosminski's symptoms in the case notes indicates that he had paranoid schizophrenia. Macnaghten's notes say that "Kosminski" indulged in "solitary vices", and in his memoirs Anderson wrote of his suspect's "unmentionable vices", both of which may match the claim in the case notes that Aaron Kosminski committed "self-abuse". Swanson's notes match the known details of Aaron Kosminski's life in that he reported that the suspect went to the workhouse and then to Colney Hatch, but the last detail about his early death does not match Aaron Kosminski, who lived until 1919 (see #Kosminski and "David Cohen").

Professor Sir Alec Jeffreys, the forensic scientist who invented DNA fingerprinting in 1984, initially commented that the find was: "an interesting but remarkable claim that needs to be subjected to peer review, with detailed analysis of the provenance of the shawl and the nature of the claimed DNA match with the perpetrator's descendants and its power of discrimination". Jeffreys and others later stated that a claim presented in the book as a statistically significant match with the DNA from Eddowes's descendant—a sequence variation described as 314.1C and claimed to be rare—was the result of an error in nomenclature for the common sequence variation 315.1C, which is present in more than 99% of people of European descent.

In 1910, Assistant Commissioner Sir Robert Anderson claimed in his memoirs The Lighter Side of My Official Life that the Ripper was a "low-class Polish Jew". Chief Inspector Donald Swanson, who led the Ripper investigation, named the man as "Kosminski" in notes handwritten in the margin of his presentation copy of Anderson's memoirs. He added that "Kosminski" had been watched at his brother's home in Whitechapel by the police, that he was taken with his hands tied behind his back to the workhouse and then to Colney Hatch Asylum, and that he died shortly after. The copy of Anderson's memoirs containing the handwritten notes by Swanson was donated by his descendants to Scotland Yard's Crime Museum in 2006.

An 1894 memorandum written by Sir Melville Macnaghten, the Assistant Chief Constable of the London Metropolitan Police, names one of the suspects as a Polish Jew called "Kosminski" (without a forename). Macnaghten's memo was discovered in the private papers of his daughter, Lady Aberconway, by television journalist Dan Farson in 1959, and an abridged version from the archives of the Metropolitan Police was released to the public in the 1970s. Macnaghten stated that there were strong reasons for suspecting "Kosminski" because he "had a great hatred of women ... with strong homicidal tendencies".

In Kosminski's defence, he was described as harmless in the asylum. He had originally been taken into custody for threatening either his sister or the sister of a witness to his admittance with a knife, and brandished a chair at an asylum attendant in January 1892, but these two incidents are the only known indications of violent behaviour. In the asylum, Kosminski preferred to speak his native language, Yiddish, which indicates that his English may have been poor, and that he was unable to persuade English-speaking victims into dark alleyways, as the Ripper was supposed to do. However, the "canonical five" killings that are most frequently blamed on the Ripper concluded in 1888; Kosminski's movements were not restricted until 1891.

In London, Kosminski embarked on a career as a barber in Whitechapel, an impoverished slum in London's East End that had become home to many Jewish refugees who were fleeing economic hardship in Eastern Europe and pogroms in Tsarist Russia. However, he may have worked only sporadically: it was reported that he had "not attempted any kind of work for years" by 1891. He possibly relied on his sisters' families for financial support, and may have lived with them at 3 Sion Square in 1890 and 16 Greenfield Street in 1891, indicating that his sisters possibly shared responsibility for caring for him and he alternated living between their family homes.

On 12 July 1890, Kosminski was placed in Mile End Old Town workhouse due to his worsening mental illness, with his brother Woolf certifying the entry, and was released three days later. On 4 February 1891, he was returned to the workhouse, possibly by the police, and on 7 February, he was transferred to Colney Hatch Lunatic Asylum. A witness to the certification of his entry, recorded as Jacob Cohen, gave some basic background information and stated that Kosminski had threatened his sister with a knife. It is unclear whether this meant Kosminski's sister or Cohen's. Kosminski remained at the Colney Hatch Lunatic Asylum for the next three years until he was admitted on 19 April 1894 to Leavesden Asylum. Case notes indicate that Kosminski had been ill since at least 1885. His insanity took the form of auditory hallucinations, a paranoid fear of being fed by other people that drove him to pick up and eat food dropped as litter, and a refusal to wash or bathe. The cause of his insanity was recorded as "self-abuse", which is thought to be a euphemism for masturbation. His poor diet seems to have kept him in an emaciated state for years; his low weight was recorded in the asylum case notes. By February 1919, he weighed just 96 pounds (44 kg). He died the following month, aged 53.

Between 1888 and 1891, the deaths of 11 women in or around the Whitechapel district of the East End of London were linked together in a single police investigation known as the "Whitechapel murders". Seven of the victims suffered a slash to the throat, and in four cases the bodies were mutilated after death. Five of the cases, between August and November 1888, show such marked similarities that they are generally agreed to be the work of a single serial killer, known as "Jack the Ripper". Despite an extensive police investigation, the Ripper was never identified and the crimes remained unsolved. Years after the end of the murders, documents were discovered that revealed the suspicions of police officials against a man referred to as "Kosminski".

Kosminski was a Polish Jew who emigrated from Congress Poland to England in the 1880s. He worked as a hairdresser in Whitechapel in the East End of London, where a series of murders ascribed to an unidentified figure nicknamed "Jack the Ripper" were committed in 1888. From 1891, Kosminski was institutionalised after he threatened a woman with a knife. He was first held at Colney Hatch Lunatic Asylum, and then transferred to the Leavesden Asylum.

Aaron Kosminski (born Aron Mordke Kozmiński; 11 September 1865 – 24 March 1919) was a Polish barber and hairdresser, and suspect in the Jack the Ripper case.

Aaron Kosminski was born in 1864 in Poland.