According to Ed Lauter, the casting director refused to see him for the role of Galloway. Lauter made a plea to George C. Scott, who then demanded that Lauter be cast.
According to "Halliwell's Film Guide", this movie "spawned the television series Police Story - Immer im Einsatz (1973) and Make-Up und Pistolen (1974)".
According to Stacy Keach, the studio initially opposed having his white character falling in love with a black woman, preferring a Hispanic or mulatto woman instead.
Apparently, Columbia Pictures paid Joseph Wambaugh, who wrote the novel on which this film was based, a bonus of $1250 for each week his novel stayed on "The New York Times" best-seller list. The novel debuted on the list on February 21, 1971, and stayed on it for 32 weeks, thereby earning Wambaugh a total bonus of $40,000.
This movie was re-titled "Precinct 45: Los Angeles Police" for its British release.