In the late 1800s, Victorian England was mesmerized and horrified by a series of brutal killings in the crowded and impoverished Whitechapel district. The serial killer, who became known as “Jack the Ripper”, had murdered and mutilated at least five women, many of whom worked as prostitutes in the slums around London. None of these murders were ever solved, and Jack the Ripper was never identified, although investigators interviewed more than 2,000 people and named more than 100 suspects. Now, 126 years after the murders, a British author, who coincidentally has just published a book on the subject, is claiming that DNA analysis has revealed the identity of the notorious killer. DNA is often thought to be the “gold standard” of human identification techniques, so why is there so much skepticism surrounding this identification?
The source of the DNA in question is a shawl, specifically a silk shawl that is purported to belong to the fourth Ripper victim, Catherine Eddowes. Eddowes was a short, intelligent and fiesty woman who had a history of drinking and financial problems. In particularly bad times, she worked as a prostitute to pay the rent. She was last seen alive at 1:35am on the night of September 30, 1888, shortly after she was released from police custody for public intoxication. A mere 10 minutes later, her body was found nearby by a policeman doing his rounds. Investigators were called, and a thorough description of the crime scene was recorded. One of the items supposedly found at the bloody scene was the shawl. However, there is no mention of the shawl in a detailed inventory of items found at the crime scene, so its provenance is questionable.
In 2007, the shawl was put up for auction by the descendants of the acting sergeant of the Metropolitan Police at the time of the investigation, Amos Simpson. According to family lore, the sergeant was the first to find the body and later got permission to take the shawl home for his wife, who put the fabric into storage, unwashed, and passed it down through subsequent generations. However, official records cannot corroborate this account. At auction, author Russel Edwards bought the shawl, hoping to prove it belonged to Eddowes and find evidence of her killer. Edwards focused his investigation on Aaron Kosminski, a Polish immigrant of Russian Jewish heritage who suffered from paranoid schizophrenia and auditory hallucinations and was committed to an insane asylum in 1891, where he died in 1919. Kosminski was one of the top suspects in the Ripper case and, at one point, was under 24-hour police surveillance.
Edwards turned to DNA analysis. In 2011, he recruited a young geneticist at Liverpool John Moores University, Jari Louhelainen, to analyze DNA isolated from blood and semen stains on the shawl along with DNA samples from maternal relatives of Kosminski and Eddowes to act as reference samples for mitochondrial DNA analysis. It is unclear whether familial DNA references were analyzed for any of the other suspects named in the case. The detailed analysis methods and results have not been published, but based on Louhelainen’s description, it appears that a buffer was applied to the fabric to draw out biological material, including DNA, which was then used for whole genome amplification followed by mitochondrial DNA sequencing. In the original article, he describes the results as follows:
“The first strand of DNA [from Kosminski’s relative] showed a 99.2 per cent match, as the analysis instrument could not determine the sequence of the missing 0.8 per cent fragment of DNA. On testing the second strand, we achieved a perfect 100 per cent match. Because of the genome amplification technique, I was also able to ascertain the ethnic and geographical background of the DNA I extracted. It was of a type known as the haplogroup T1a1, common in people of Russian Jewish ethnicity. I was even able to establish that he had dark hair.”
He also shows that mtDNA extracted from the shawl matched perfectly mtDNA from Eddowes relative. Thus, these results suggest that the shawl contains DNA from the maternal lineages of both Kosminski and Eddowes or from someone with the same mtDNA haplogroup. While it is difficult to judge the validity of these results because the data have not been subjected to peer review, let’s assume for a moment, just for argument’s sake, that the results are valid. We still cannot draw conclusions about how the DNA was deposited on the shawl. For example, the shawl could have been handled by one of their relatives, or anyone else with the same mtDNA haplogroup, before or after the crime was committed. Also, the Kosminski DNA was taken from a semen stain on the shawl of a known prostitute, but experts have found no evidence of sexual activity at the Jack the Ripper crime scenes (1). Perhaps most importantly, there is reasonable doubt as to whether the shawl was found at the crime scene in the first place; the fabric is not mentioned in the crime scene inventory. Thus, it is impossible to say with certainty that the shawl belonged to Eddowes. It is also impossible to say that Kosminski was her killer.
Edwards would like us to believe that the DNA evidence proves the identity of Jack the Ripper. As a scientist familiar with DNA typing, I remain skeptical. There are too many questions that remain unanswered. In addition, I can’t help but wonder why these results were published in the British tabloid the Daily Mail and not a peer-reviewed journal, where the results must undergo scientific scrutiny before publication. Before you draw your own conclusions though, be sure to read the original article, then let me know what you think.
- Keppel, R.D. et al. (2005) The Jack the Ripper murders: A modus operandi and signature analysis of the 1888–1891 Whitechapel murders, J. Investigative Psychology and Offender Profiling, 2, 1–21.
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