As soon as Patricia Cornwell's book naming Walter Sickert as Jack the Ripper was published, dedicated Ripperologists set about poking holes in her theory and methods. One critic, a curator of Sickert works at the Royal Academy in London, called her "monstrously stupid" for destroying a Sickert painting in the name of research [source: The Guardian].
Other criticism has been leveled more at Cornwell's conclusion. Chief among this criticism from Ripperologists is her use of mitochondrial DNA.
We receive our mtDNA from our mother's lineage only, which makes it less accurate in identifying our cells than the unique combination of DNA found in our cells' nuclei [source: ORNL]. While Cornwell's mtDNA sample ruled out 99 percent of the population, this still left nearly 50,000 other London residents in addition to Sickert who may have produced an mtDNA match as well.
Ripperologists critical of Cornwell point out that if Walter Sickert were the man who sent the Ripper letters that provided this DNA match, this doesn't prove he was also the killer. Sickert was well-known for his prolific letter writing to the editors of local newspapers. He was also very much interested in the Ripper murders. So it's perhaps less of a stretch to assume that Sickert wrote the letter as a bizarre prank than it is to assume that because he wrote the letters, he was the Ripper.
The use of paintings as evidence is also called into question by some Ripperologists. As anyone interested in art knows, paintings are open to interpretation by the observer. But Ripperology puts little stock in art appreciation. While Sickert's paintings can be taken to depict dead women, they could also be sleeping or resting women. The one work of Sickert's that's most often cited as evidence of the painter's guilt is "The Camden Town Murder." But as Ripperologist Wolf Vanderlinden points out, Sickert gave this painting an alternate title: "What Shall We Do for Rent?" Under this other title, the menace in the painting is replaced by a sense of desperation and uncertainty: Murderer and victim become simply a couple who've fallen on hard times [source: Vanderlinden].
It's possible that Sickert did use the murdered women as subjects for his paintings. It's also possible that the artist did so as an attempt at grisly humor or simply out of interest in the Ripper case -- art imitating life. Cornwell's assertion that Sickert only painted things he saw in real life is undermined by evidence that Sickert did, in fact, paint from photographs on occasion -- especially later in life. And when the artist produced his most "confessional" paintings around 1905, a book containing photos of the Whitechapel murder victims had already been published for six years [source: Vanderlinden].
Ultimately, there are too few clues to definitively identify Walter Sickert or any of the other suspects as Jack the Ripper. While Patricia Cornwell is satisfied with her closed case, the century-old manhunt continues for Ripperologists pursuing their own theories.
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