I’m pretty sure it’s directly referencing the opening credits of Casino although the music is Bach’s “St. Matthew’s Passion” not “Ave Maria”.
That said, contrasting a violent scene with pretty or serene music is a pretty common in cliche in gangster movies. Besides the ones mentioned above, another favourite of mine is the Danny Boy shootout scene in “Miller’s Crossing”.
Cowboy Bebop has a gunfight to Ave Maria.
Last night I watched Dom Hemingway and there was a scene of that type. It’s a fairly recent movie so I’ll put it in spoilers even though it’s probably not necessary:
At one point Dom (played by Jude Law) and some other people are careening down a rainy mountain road in a convertible (after an evening of alcohol & coke) when they crash into another car. It goes into slow motion with operatic music as the occupants are thrown through the air, head over heels, champagne bottles flying and rain pouring down. One of the passengers, Dom’s ex-crime partner, has a prosthetic hand which comes off and goes slowly spinning by. It’s a pretty funny scene, I wish I could find it on Youtube.