There is other physical evidence as well. Forensic scientists as well as art, paper, and lettering experts found the following: a Ripper letter written on artists' paper; watermarks on paper used in Ripper letters that match watermarks on paper used by Walter Sickert; Ripper letters written with the waxy-soft crayonlike ground used in lithography; Ripper letters with paint or ink applied with a paintbrush. A microscopic exam revealed that the "dried blood" on Ripper letters is consistent with the oil-and-wax mixtures used in etching ground, and under ultraviolet light it fluoresced milky white, which is also consistent with etching ground. Art experts say that sketches in Ripper letters are professional and are consistent with Walter Sickert's art works and technique.

As an interesting aside, a blood-detection test conducted on the blood-like etching ground smeared and painted on Ripper letters came up as inconclusive - which is very unusual. Two possible explanations are as follows: It could be a reaction to microscopic particles of copper, since in this type of testing copper could cause inconclusive results or a false positive; or it could be the presence of blood mixed with the brown etching ground.

Handwriting quirks and the position of the Ripper's hand when he wrote his taunting, violent letters lurk in other Ripper writings that are disguised. These same quirks and hand positions lurk in Sickert's erratic handwriting as well.

Paper of letters the Ripper sent to the Metropolitan Police precisely matches paper of a letter the Ripper sent to the City of London Police - even though the handwriting is different. It is evident that Sickert was right-handed, but video footage taken of him when he was in his 70s shows he was quite adept at using his left hand.