The Dark Past (1948)

The Dark Past (1948) is one of several films noir which opens with the aerial shot of the city, and an earnest voice over describing the existential experience of the urban life, the technological alienation which is suggestive of an architectural emptiness, a nihilism even, akin to crime in its freedom.

As Side Street seems to open with the message that any one of us may be the day's murder victim as much as they may be that murder's suspect.

The Dark Past takes the more traditional Mark Hellinger informed attitude that this is the naked city, and that it's like a jungle sometimes, and this is our framing, the real life city.

William Holden plays mean as hell psychopath and killer Al Walker, a film noir apogee and the defining casting action of a style which elevated to central protagonist the idea of villain as narrative prime mover.

Act of Violence (1949)

A former prisoner of war, Frank Enley (Van Heflin) is hailed as a hero in his California town.

However, Frank actually aided his Nazi captors, and he closely guards this secret!

Frank's shameful past comes back to visit him when fellow survivor Joe Parkson (Robert Ryan) emerges, intent on making the turncoat pay for his betrayal. 

As Joe closes in on Frank, the traitor goes into hiding, abandoning his wife, Edith (Janet Leigh), who has no clue about her husband's wartime transgressions. When Frank begins to truly fear his nemesis, played by the relentlessly limping Robert Ryan, he begins to speak of him as if he were speaking of the stalking figure of death itself. 

And his paranoia is total:

"You don't know what made him the way he is - I do!"