Italian cop movies of the 60's & 70's, or poliziotteschi, were some of the grittiest, most violent, and, yes, grooviest ever made. Police corruption, syndicates, and violent killers were common themes in these pictures.
Some of the grooviest poliziotteschis were directed by luminaries of Italian cinema such as: Enzo Castellari, Alberto De Martino, Damiano Damiani, Sergio Sollima, Umberto Lenzi, and Sergio Martino to name a few, and frequently starred greats Fabio Testi, Franco Nero, Tomas Milian, or the fabulously blonde and mustachioed Maurizio Merli. It would not be unusual to see British actors in prominent roles as well. David Hemmings in La Via Della Droga and Oliver Reed in Revolver come to mind, even the venerable James Mason got into the act.
Now the point of all this is the music. These movies had amazing music! Many of the greats of Italian soundtrack composing got into the act. Morricone, Cipriani, Goblin, Micalizzi, and on and on. The music is rhythmic and pulse pounding. One of my favorite songs is Goodbye, My Friend by brothers Guido and Maurizio de Angelis from the soundtrack to Il Cittadino si Ribella. Check it out.