From pp 91-92:

Sims, who had a curious passion for the ghastly, always maintained that he knew the identity of "Jack the Ripper," and that his knowledge was also shared by the police. I vividly remember an evening in the study of his house in Regent's Park, when from a bureau he produced a horrible series of photographs of the "Ripper's" victims, the mutilations and wounds being emphasized in red ink.

Sims himself had once been suspected of the "Ripper" murders, and, in fact, was not unlike the criminal in appearance. The night of the double murder which horrified London, a coffee-stall keeper noticed a customer had blood on his cuffs.

"The Ripper's pretty lively just now," he remarked: and the man replied: "Yes, and you may hear of more murders to-morrow," and walked away. Next day, when teh town rang with the new crimes, the stall-keeper noticed Sims' portrait on a bookstall. "That's the man!" he exclaimed, and reported his discovery to the Yard.

According to Dagonet, the mysterious criminal was a doctor with homicidal mania of a peculiarly vile kind, who had previously been confined in a lunatic asylum.

His body was found in the Thames, and the police inquiries came to an end, for you can't try a dead man.