The film's premise of the plot behind the murders is influenced by the book "" (1976), by Stephen Knight, who presumed that the killings were part of a Masonic plot. The original script contained the names of the historical suspects, Sir William Gull and John Netley. In the actual film, they are represented by fictional analogues: Thomas Spivy (Gull) and William Slade (Netley). This plot device was later used in other Jack the Ripper-themed fiction, including the graphic novel "From Hell."