The script for this movie was originally picked up by New Line Cinema, with the intention to re-write it as a sequel to Se7en (1995), tentatively titled "Ei8ht". The main character was supposed to be Se7en (1995)'s Detective William Somerset (Morgan Freeman), who had acquired psychic powers. This idea was dropped after Se7en (1995) director David Fincher reacted negatively to the idea, after which it was produced as a stand-alone movie.
After spending close to two years in the Warner Brothers vault, this movie was bought by Relativity Media to release in the U.S. However, they never released it due to their bankruptcy, and it was sold again to Lionsgate Premiere.
At around 10:30), when John (Sir Anthony Hopkins) is listening to the aria from La Boheme, the character Rodolpho from the opera sings (in Italian) "Who am I?" just as the words "Who am I?" appear on-screen as part of the case file John is starting to review.
The poem quoted by Charles Ambrose (Colin Farrell) and John Clancy (Sir Anthony Hopkins) is the first part of "The Leaden Echo and the Golden Echo" by Gerard Manley Hopkins.
This movie was originally going to be directed by Shekhar Kapur, with Bruce Willis in the lead role.