James Ellroy wrote the screenplay in the mid-1990s, inspired by the O.J. Simpson trial. Over the years, Spike Lee, David Fincher, and Oliver Stone were attached to direct the film, at various stages of pre-production. John Ridley contributed to an early version of the screenplay. Belgian Director Erik Van Looy was set to direct this film, according to various interviews, but these plans were scrapped in pre-production, upon which Van Looy went on to direct Loft (2008) in Belgium.
Early in the film, Captain Wander (Forest Whitaker) instructs two of his officers to return to the station house, which he refers to as "the barn", a possible reference to The Shield (2002), in which Whitaker had a starring role prior to this film.
The trivia items below may give away important plot points.
When Detective Tom Ludlow (Keanu Reeves) first meets Detective Paul Diskant (Chris Evans) in his office, he subsequently leaves the office and says, "Harry, I thought you were dead!" This is a reference to Speed (1994), where Jack (Keanu Reeves) has a partner called Harry (Jeff Daniels), who was killed in a house bombing.
During the funeral scene for Detective Washington (Terry Crews), Chief Daryl Gates makes a cameo appearance. He can be seen saluting prior to the gun salute, and again as he's walking away with Captain Wander (Forest Whitaker).