“Heat” was inspired by a real cops and robbers tale, about a bank robber named Neil McCauley who, in 1964, was shot dead by Chicago Detective Chuck Adamson. Given the fate of the real McCauley, there was no other possible fate for his silver screen counterpart.

Mann, who first heard the story of McCauley and Adamson in 1979-1980, wrote the script that became “Heat” afterward. This was before Man had even made his directorial debut in 1981 with “Thief.” The project then spent 15 years in development; Mann had a chance to film the story as a TV movie, “L.A. Takedown,” but the results were underwhelming.

In an interview with Scraps from the Loft, Mann revealed the image of the ending, mirroring the end of Adamson and the real McCauley’s encounter, is what drove him to see “Heat” realized as a feature.

“I had most of it there. But you know when you know. And I knew when I figured out exactly what happened in the end and I took that dialectical conclusion and worked it backwards into the structure and modified everything that was going on to serve that, that’s when it all clicked into place for me.”

Notice how Mann describes the ending as “dialectical,” or two opposites coming together. That’s literally what McCauley and Hanna become in the final shot; they’re far enough apart that their figures remain distinct, but still connected by their outstretched hands. Two sides of the same coin, Hanna and McCauley, law and criminality, life and death, finally come together only after their struggle is over.