When Keanu Reeves character first meets Chirs Evans character in his office, he subsequently leaves the office and says "Harry, I thought you were dead?" This is a reference to Speed (1994) where Keanu Reeves character has a partner called Harry (Jeff Daniels) who was killed early on in a house bombing.
James Ellroy wrote the screenplay in the mid-1990's 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. Sean Penn was once attached to star. 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 preproduction, upon which Van Looy went on to direct Loft (2008) in his home country.
Early in the film, Capt. 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' in which Whitaker had a starring role prior to this film.
During the funeral scene for Det. Washington (Terry Crews), 43-year LAPD veteran, Chief 'Daryl Gates' (I) makes a cameo. He can be seen saluting prior to the gun salute and again as he's walking away with Capt. Wander (Forest Whitaker).