Ruth Wilson was cast as Jo Durkin (who is a male character in the books), and filmed all of her scenes as Liam Neeson's partner. But director Scott Frank felt that Neeson's character should be a loner, so all of Wilson's scenes were cut.
Thanks to Liam Neeson's popularity with past action hits, the film was already in profit before release, thanks to robust sales at film markets.
Second appearance of character Matt Scudder. The first time, it was played by Jeff Bridges in Huit millions de façons de mourir (1986).
The name of all three murdered women are allusions to the figure of Jesus Christ: Gotteskind (Marie Gotteskind, played by Marielle Heller, meaning "Child of God" as pointed out by T.J. (Astro); Andersen (Leila Andersen, played by Laura Birn), meaning "Son of Man"; and Kristo (Carrie Kristo, played by Razane Jammal), from which the title "Christ" derives.