The movie's MacGuffin was a mysterious anonymous letter written in Hebrew and known as a "goel hadam" note. "Goel Hadam" is a Hebrew/Jewish phrase which translates into the English language as an "Avenger of Blood".
Miklós Rózsa score for this film was composed in the style of regular Hitch music composer Bernard Herrmann who worked regularly with thriller director Alfred Hitchcock. Music composer Rózsa had actually worked with Hitchcock himself once, on 1945's Spellbound (1945).
The quote read out by Rabbi Drexel (David Margulies) from the Hebrew Bible was from Deuteronomy, chapter 19, verse 12. It said: "Then the elders of the city shall send and fetch him thence and deliver him into the hand of the avenger of blood that he may die".
Many major movie posters for the film featured a blurb that read: "It begins with an ancient warning. It ends at the edge of Niagara Falls. In between there are 5 murders. Solve the mystery. Or die trying".
This Hitchcockian style movie was directed by Jonathan Demme who would go on later to direct the documentary Storefront Hitchcock (1998) just under twenty years later which was actually completely unrelated to Hitch and wasn't actually about Alfred Hitchcock but British singer-songwriter Robyn Hitchcock. Demme though did go onto to direct the 5 Oscar and Best Picture Academy Award winning suspense-thriller The Silence of the Lambs (1991) in 1991.