You've probably heard the news that Jack the Ripper has finally been identified. New research by an amateur sleuth claims that DNA evidence shows that a man named Aaron Kosminski was London's most infamous serial killer, stalking the city in the 1880s.
The news was reported in the Daily Mail, and a piece on Discovery News noted that "Molecular biologist Dr. Jari Louhelainen tells the Mail on Sunday that he used a technique called ‘vacuuming' to remove DNA from a stained shawl purportedly belonging to one of the victims, Catherine Eddowes. Businessman Russell Edwards had bought the shawl at an auction in 2007, and had asked Louhelainen to help him find any clues that may be connected with the Ripper case."
There is of course a book deal in the works for Edwards, and these "revelations" have been met with skepticism for many reasons, including the fact that the shawl that provided the DNA implicating Kosminski has a dubious provenance - there's no clear or proven connection between the shawl and Ripper victim Eddowes. It might have been hers found at the crime scene, or it might not. Even if it was hers, it might have Jack the Ripper's blood on it - or it might not. A study published in a peer-reviewed science journal would bolster its credibility.
Still, if the case seems compelling to you, there's a good reason why, and it has less to do with the evidence than psychology. Dozens of books have been written, each claiming to reveal the true identity of Jack the Ripper and offering what seems to be strong evidence for their suspect. The problem is that most of them point the finger at different people. Each writer selectively chooses what evidence to present that supports their suspect, and ignores or dismisses evidence to the contrary.
This isn't an attempt to cover anything up, but instead a common and powerful psychological phenomenon called confirmation bias. When it comes to researching information, we tend to seek out information that supports our beliefs and assumptions. Psychologist Thomas Gilovich, in his book "How We Know What Isn't So: The Fallibility of Reason in Everyday Life," notes:
"When examining evidence relevant to a given belief, people are inclined to see what they expect to see, and conclude what they expect to conclude. Information that is consistent with our pre-existing beliefs is often accepted as face value, whereas evidence the contradicts them is critically scrutinized and discounted."
In legal terms, writers and researchers are acting as prosecutors, presenting evidence that their favored suspect is guilty. But there's no real defense, since the person being identified as the Ripper is long dead and no one is doing an equal amount of research trying to prove that the suspect is innocent (aside, perhaps, from a token effort by rival authors who have their own agendas). When you only hear one side of the story of course it's convincing - until you read the next book or see the next Ripper-based movie.
Ripper Suspects Edwards's DNA identification of Kosminski may seem very compelling - until, for example, you read the 400-page, 1998 book "Prisoner 1167: The Madman Who Was Jack the Ripper," which builds a convincing case that a man named James Kelly was the infamous killer. Kelly was an upholsterer who killed his wife by cutting her throat, and who was then committed to a mental institution, escaping just before the Ripper's bloody spree started.
The evidence laid out seems persuasive - but then again so did the two-part TV miniseries that aired a decade earlier titled "Jack the Ripper," starring Michael Caine. The series began with a based-on-a-true-story tone assuring viewers that the Ripper had finally been unmasked: "Our story is based on extensive research, including a review of the official files by special permission of the Home Office and interviews with leading criminologists and Scotland Yard officials."
This time the evidence suggested that the killer was Sir William Gull, Royal Surgeon to Queen Victoria, whose crimes were covered up in a conspiracy of silence.
Yet the implication of Gull as the Ripper had been made decades earlier by several writers, including Stephen Knight, author of the now-discredited 1976 book "Jack the Ripper: The Final Solution." Despite such bold claims and breathless titles, many researchers doubt that Gull was involved.
Given the exhaustive research brought to bear on the Ripper killings, it's virtually certain that Jack the Ripper has already been identified. Over a hundred people have, at one time or another - and with wildly varying degrees of evidence and certitude - been implicated as Jack the Ripper.
At this point, over 125 years after the murders, it's unlikely that any new, credible suspects will be added to the list. Ripperologists, as they call themselves, have identified about a dozen or so most likely suspects, and most "new" revelations and evidence is simply additional support for one of those previously identified.
Obviously they can't all be Jack the Ripper, and so all the claims should be met with a healthy dose of skepticism. Kosminski may indeed be Jack the Ripper - and in fact he has long been considered one of several prime suspects - but in coming years equally convincing evidence and books will argue that it's someone else.
There are strengths and weaknesses in each case, and there are only so many data points to work from. Whose image appears in those data points depends entirely on how those dots are connected, and there's plenty of rumor and conjecture to fill in the gaps.