Are YOU Jack The Ripper? No. And neither’s Aaron Kosminski

Yesterday, the Daily Mail reported that it had, after more than a century of speculation, solved the mystery of Jack The Ripper

The Mail could exclusively reveal the killer to be… an Eastern European immigrant.

Typical bloody Poles, coming over here, stealing the jobs that could have been done by our hard-working British serial killers…

So, is that right? Has one of the greatest mysteries in forensic science just been solved by the newspaper than claimed that bread both cures and causes cancer?

Probably not. And here’s why…

Reason #1: The Source

This paper says it’s definitely true

The Mail claims that DNA analysis has identified Polish barber Aaron Kosminski as being Jack the Ripper. Which is great news. Those are the sorts of the results that would definitely be published in a reputable, peer-reviewed journal, right?

Well… Sort of. They come from an article written to promote the publication of a new book, Naming Jack The Ripper by Russell Edwards, which is published tomorrow and costs £16.99.

Pretty lucky that this story happened to break two days before publication, right?

And also pretty lucky that they found the identity. Otherwise the book’s title would have been a little embarrassing. Fortunately, as Mr Edwards – who also coincidentally runs the Official [sic] Jack The Ripper Store (which opened in July) in London’s fashionable, murderous East End – says: “I became convinced Kosminski was our man, and was excited as the prospect of proving it.” Which would explain why they didn’t test the DNA of the descendants of any of the other suspects.

We have yet to hear the response of the last person to come up with a “definitive, forensic” solution for the Ripper killings. Patricia Cornwell wrote Jack The Ripper: Case Closed when she found out it was definitely Walter Sickert, through forensic analysis of letters sent to the police and mitochondrial DNA.

Reason #2: The Shawl

Russell Edwards, handling DNA evidence without gloves

All of the valuable DNA evidence came from the shawl that Mr Edwards is holding above. So what do we know about the shawl?

  • It’s not a shawl Look at it. It’s not a shawl. It measures 8 feet by 2 feet. Unless Catherine Eddowes was a thin, rectangular woman of incredible height, it’s not a shawl.


  • Catherine Eddowes didn’t own it As Mr Edwards points out, the day before she was murdered, Catherine Eddowes had to pawn her own shoes, so she was unlikely to have a finely-wrought shawl of Michaelmas daisies to hand. Mr Edwards think that Jack the Ripper gave it to Catherine before murdering her on it, and leaving it as a deliberate clue.


Except: it wasn’t at the crime scene

We’ve got a fairly detailed inventory of the things found at the crime scene. There is no mention of a shawl like this one.

Mr Edwards’ belief that the ‘shawl’ has anything at to do with the murders comes from one letter. A letter owned by the person who sold him the shawl. A letter that says a police constable who is never recorded as being at the crime scene, and whose beat didn’t encompass it, got to the crime scene first, and took the shawl home for his wife, who was a dressmaker. She didn’t like the bloodstains, and so wouldn’t use it, and so they kept it hanging around, unwashed for 126 years.

Mr Edwards says it is “incredible” that no one washed it in that time. And he’s right. In that it’s “unbelievable” that anyone should be so horrified by the bloodstains on a garment that they should decide to preserve it in its bloodstained state.

So it’s a shawl that’s not a shawl that was never at the crime scene that was stolen by a policeman who was also never there whose wife was so disgusted by it that he preserved it in a fashion good enough to collect forensic evidence from over a century later.

But, as many people have pointed out, there’s every chance of contamination during that period. Above, you can see Mr Edwards handling it without gloves, and it’s been taken to conferences and exhibitions (one of which refused to display it because of the doubts about its provenance). At least once it’s been in the same room as the descendants of Catherine Eddowes, who, unsurprisingly, would be a good mDNA match for other descendants of Catherine Eddowes.

But what about the DNA? The DNA shows that Catherine Eddowes’ blood and Kosminski’s semen are on the shawl?

Well… does it?

Reason #3: The Process

Some DNA, kicking it mitochondrial-style

Okay, leaving aside the questions over the contamination of the sample and the small issue of peer review, surely the evidence is clear?

Except it’s not quite that simple. Because there was no nuclear DNA available from the sample, the researchers were forced to work from mitochondrial DNA, which can show common maternal ancestors, but isn’t much use for identifying individuals within a group.

The slow rate of mutation for mtDNA means that there are only mutations about every 40 generations or so, so when you have a perfect match on mitochondrial DNA, that means that the two samples shared the same maternal ancestor within the last 40 generations roughly. Or 1,000 years.

Even given all the other questions, all the results tell us is the descendants of Catherine Eddowes and relatives of Aaron Kosminski shared a common maternal ancestor at some point since Macbeth made himself king of Scotland.

Tellingly, scientists who work in developing DNA profiling don’t seem as convinced as the Daily Mail

Peter Gill, a pioneer in DNA profiling said “The shawl is of dubious origin and has been handled by several people who could have shared that mitochondrial DNA profile. Normally you go for peer-review before going to the press. This hasn’t been reviewed by the scientific community.”

Professor Sir Alec Jeffreys, who invented DNA fingerprinting, said: “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; no actual evidence has yet been provided,”

But what about the blood? And the semen? And how are you going to find an image to head that section?

Reason #4: The Samples

Bloody Seaman

Even if we leave aside all the questions raised above, we should probably acknowledge that, as Catherine Eddowes was a prostitute, finding traces of semen on her clothing is not evidence that the person who produced that semen killed her. Unless you have a weird theory that Jack the Ripper gave Eddowes the shawl only to promptly murder her.

So, have we discovered who the Ripper was?

No, and there’s evidence that Kosminski was historically considered as a suspect precisely because he was a Jewish Pole.

What we have learned was that there is an unverified possibility, using a sample of dubious provenance, that suggests that the relatives of both Catherine Eddowes and Aaron Kosminski shared matrilineal ancestors with two people who may or may not have touched what might or might not be a shawl at some point in the last 1,000 years.

Oh, and we’ve also learned that Russell Edwards has a book to sell. Which you can buy in his shop.

Thanks to @SciWhat and @DonTheDazzler for science…


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