Page "Portrait of a Killer: Jack the Ripper—Case Closed" Paragraph 2

Jean Overton Fuller, in her 1990 book Sickert and the Ripper Crimes, had maintained that Sickert was Jack the Ripper.

Prior to that, Stephen Knight, in his 1976 book Jack the Ripper: The Final Solution, had maintained that Sickert had been forced to be an accomplice of the Ripper.

Neither of these two books is mentioned in Cornwell's book.