matter of coincidence. In the end, although the evidence is certainly not iron-clad, it can be considered suggestive. Ignoring the various pitfalls of contamination and provenance, the mtDNA evidence does show that Walter Sickert can not be eliminated from suspicion of having written, or hoaxed, one or more Ripper letters. Walter Sickert Concept #3: Patricia Cornwell has found similar watermarks, as well as similar names, phrases and drawings in both the "Ripper" correspondence and the Sickert letters. Ms. Cornwell notes that three distinct watermarks are found in both the Ripper and the Sickert letters - A. Pirie & Sons, Joynston Superfine and Monckton's Superfine. She also notes that the name "Nemo" is found in several Ripper letters. "Nemo" was a favorite stage-name used by Walter Sickert in his acting days. Similar phrases and doodles appear similar as well. Fact #3: Considering the incredibly vast number of documents within the "Ripper" correspondence, the laws of chance dictate that eventually, coincidental similarities will appear. Remember that Ms. Cornwell had approximately 600 "Ripper" letters to sift through during her research, as well as many hundreds of documents belonging to Sickert. Eventually, if one is persistant enough, one will find similarities. This is a common pitfall in Ripperology. Countless times, researchers have started out with a suspect in mind, and then scanned the Ripper correspondence for evidence that might link it with their suspect. If their suspect was a doctor, they had a dozen or so letters from people claiming to be a doctor.