Touch of Evil

It was a passion project. It was Orson Welles' baby. It was "Touch of Evil," released in 1958. It stars Charlton Heston as Miguel Vargas, Janet Leigh as Mrs. Vargas, and Orson Welles as Police Captain Quinlan.
I would consider this film to be a defining one for film noir. The film is centered around a border town between Mexico and the United States. This is important, because the border-town creates an entire culture unto itself. The story is dark, as well as the surroundings.
The story starts as a panoramic view of the border town's nightlife. Having just crossed the border, a car suddenly explodes. Both Vargas (a top Mexican narcotics official) and Quinlan are drawn into the investigation because of the location.

The investigation of the murder unravels simultaneously to the raveling up of mysteries. Vargas is a good detective, perhaps too much for his own good. His wife becomes an instrument of implication and deception. Everyone has to make a decision and ultimately those decisions will never come to fruition and choices were made for naught. It is the washed-up, tarot card-reading prostitute who has the last word.