Angelina Jolie has admitted in interviews she shot nude scenes for this movie, but Director Phillip Noyce cut them, feeling they distracted from the story.
When Amelia jumps into the river to rescue the old man and his granddaughter, she was actually jumping into a heated pool. A vegetable dye was added to give the water its appearance.
In Jeffery Deaver's novel, Amelia Donaghy (Angelina Jolie) was named Amelia Sachs. The filmmakers changed it, because it "sounded a lot like 'sex'".
At the end, at Lincoln's Christmas party, you see Paulie's (Ed O'Neill's) family. It consists of a redheaded wife, a blonde daughter, and a dark haired son. This family mirrors Al Bundy's family in the television show Married with Children (1987), for which Ed O'Neill is best known.
Angelina Jolie's real-life modeling career was written into the script, to make it seem more believable for her to be a New York City beat cop.
DIRECTOR_CAMEO(Phillip Noyce): A man browsing through books in the bookstore that Angelina Jolie enters.
John Benjamin Hickey (Dr. Barry Lehman) and Luis Guzmán (Eddie Ortiz) also appeared with Denzel Washington in The Taking of Pelham 123 (2009).