"My theory of the crimes is that the criminal has been badly disfigured," says an October 4, 1888, letter filed with the Whitechapel Murders papers at the Corporation of London Records Office, " - possibly had his privy member destroyed - amp; he is now revenging himself on the sex by these atrocities." The letter is written in purple pencil and enigmatically signed "Scotus," which could be the Latin for Scotsman. "Scotch" can mean a shallow incision or to cut. Scotus could also be a strange and erudite reference to Johannes Scotus Eriugena, a ninth-century theologian and teacher of grammar and dialectics.

For Walter Sickert to imagine Whistler in love and enjoying a sexual relationship with a woman might well have been the catalyst that made Sickert one of the most dangerous and confounding killers of all time. He began to act out what he had scripted most of his life, not only in thought but in boyhood sketches that depicted women being abducted, tied up, and stabbed.

The psychology of a violent, remorseless murderer is not defined by connecting dots. There are no facile explanations or infallible sequences of cause and effect. But the compass of human nature can point a certain way, and Sickert's feelings could only have been inflamed by Whistler's marrying the widow of architect and archaeologist Edward Godwin, the man who had lived with actress Ellen Terry and fathered her children.

The sensuously beautiful Ellen Terry was one of the most famous actresses of the Victorian era, and Sickert was fixated on her. As a teenager, he had stalked her and her acting partner, Henry Irving. Now Whistler had links to not one but both objects of Sickert's obsessions, and these three stars in Sickert's universe formed a constellation that did not include him. The stars cared nothing about him. He was truly Mr. Nemo.

But in the late summer of 1888 he gave himself a new stage name that during his life would never be linked to him, a name that soon enough would be far better known than those of Whistler, Irving, and Terry.