Quiz

This was the third film starring Sidney Poitier as Virgil Tibbs, following La calda notte dell'ispettore Tibbs (1967) and Omicidio al neon per l'ispettore Tibbs (1970). With this entry, Virgil Tibbs became one of the first, if not the first, cop movie series made in color to make it to part three (the Ispettore Callaghan: il caso 'Scorpio' è tuo!! (1971) movies did not start until the same year that this film came out).

The first line of dialogue only occurs eight minutes into the movie, the second six minutes later, when the heist is over. Apart from that one line, the entire heist is done without any dialogue, which is reminiscent of the wordless robbery scene in Rififi (1955).

Max Gail's film debut.

In 1971, United Artists distributed this film on a double bill with Io sono la legge (1971) starring Burt Lancaster and Robert Ryan.

The tunnel scene is filmed in the BART tunnel which can be seen still under construction. It would begin service the following year, Sept. 1972.