Forensic scientists say they have the identity of Jack the Ripper, the notorious serial killer who terrorized the streets of London more than a century ago, discovered. Genetic tests released this week point to Aaron Kosminski, a 23-year-old Polish barber and a police suspect. However, critics say the evidence is not strong enough to declare the case closed.
The findings are from a forensic investigation of a stained silk scarf that investigators claimed was found next to the mutilated corpse of Catherine Eddowes, the murderer's fourth victim. 1888. The cloth is spattered with blood and semen, which are believed to come from the murderer. Four other women were murdered in London in a three-month spree, and the perpetrator was never confirmed.
This is not the first time that Kosminski has been linked to the crime. However, it is the first time that the supporting DNA evidence has been published in a peer-reviewed journal. The first genetic tests on cloth samples were carried out a few years ago by Jari Louhelainen, a biochemist at John Moores University in Liverpool, UK. However, he said he wanted to wait until the excitement faded before presenting the results. Author Russell Edwards, who bought the cloth in 2007 and presented it to Louhelainen, identified Kosminski as a murderer in a 1945 book titled Jack the Ripper (19459022) based on unpublished test results. However, geneticists complained at the time that the claims could not be appraised because few technical details were available on the analysis of genetic samples from the tissue.
The new paper notes this to some extent. In what Louhelainen and his colleague David Miller, a reproductive and semen expert at the University of Leeds in the UK, claim are "the most systematic and advanced genetic analysis of the Jack the Ripper killers yet" They extract and amplify the DNA from the tissue. In the tests, fragments of mitochondrial DNA – the part of DNA inherited only from the mother – were removed from the tissue and compared to samples from living descendants of Eddowes and Kosminski. The DNA corresponds to that of a living relative of Kosminki, they conclude in the Journal of Forensic Sciences .
The analysis also suggests that the killer had brown hair and brown eyes, which is consistent with eyewitness eyewitnesses. "These features are certainly not unique," the authors admit in their work. The blue eyes are now more common in England than brown, the researchers say.
The results should not satisfy the critics. Important details about the specific genetic variants that are identified and compared between DNA samples are not included in the paper. The authors instead present them in a graphic with a row of colored boxes. If the boxes overlap, they say, the cloth and the modern DNA sequences overlap.
The authors say in their article that the Data Protection Act, a UK privacy law for individuals, prevents them from identifying the genetic sequences of the living relatives of Eddowes and Kosminski. It is said that the graphics in the paper are easier for non-scientists to understand, especially for those "interested in real crime".
Walther Parson, forensic scientist at the Institute for Legal Medicine of the Medical University of Innsbruck in Austria, says mitochondrial DNA sequences pose no risk to privacy and the authors should have included them in the work. "Otherwise the reader can not judge the result. I wonder where science and research will go if we start to avoid results, but present colored boxes. "
Hansi Weissensteiner, an expert on mitochondrial DNA also in Innsbruck, contradicts mitochondrial DNA analysis, which he says only reliably shows that individuals or two DNA samples are not related to each other. "Based on mitochondrial DNA, one can only exclude one suspect." Mitochondrial DNA from the cloth could come from Kosminski, but it could also be from thousands living in London at the time.
Other critics of the Kosminsky theory have pointed out that there is no evidence that the cloth has ever been found on the scene. It could also have been contaminated over the years, they say.
The new tests are not the first attempt to identify Jack the Ripper by DNA. A few years ago, US crime author Patricia Cornwell asked other scientists to analyze DNA in samples from letters allegedly sent by the serial killer to the police. Based on this DNA analysis and other clues, she said the killer was the painter Walter Sickert, although many experts believe these letters are wrong. Another genetic analysis of the letters claimed the killer could have been a woman.