Before “Jaws,” the fledgling director was attached to a much darker thriller.

Back in the early 1970s, while George Lucas was immortalizing the “cruising” culture of teens and their cars in “American Graffiti,” his future frequent collaborator Steven Spielberg was exploring a different kind. Nearly a decade before director William Friedkin created a scandal with the Al Pacino-starring “Cruising” (released 37 years ago today), the wunderkind filmmaker—who has won over generations of audiences by evoking a childlike sense of wonder—almost made his leap from TV to features with the most adult-themed project imaginable.

It all started with producer Philip D’Antoni, who had won an Oscar for the 1971 drug-bust saga “The French Connection” and was looking for a filmmaker to helm another New York City-set crime project. He had just bought the rights to the novel “Cruising,” written by The New York Times feature writer Gerald Walker, in which an undercover cop descends into the leather bars of Greenwich Village as he tracks a homosexual murderer. D’Antoni met Spielberg in Los Angeles in the early ’70s, and hired the young director to work on “Cruising” after seeing his made-for-TV movie “Duel,” which depicts a man being pursued by a mysterious truck driver. “He came out to New York and I put him up in a hotel for a month, and we got to know each other very well,” D’Antoni recalled in an interview.

READ MORE: Return of the Repressed: William Friedkin’s ‘Cruising’

He also connected Spielberg with Randy Jurgensen, one of the behind-the-scenes heroes of the New York cop-movie genre in the ’70s. An NYPD detective for two decades, Jurgensen was part of the “Seven-Ups” squad that inspired D’Antoni’s 1973 film of the same title, and a technical advisor on “The French Connection” and numerous other films of the era. Jurgensen has clear memories of his encounters with Spielberg: “I found myself being interviewed by a very young, thin gentleman with glasses, and he had lots of questions,” he said. “I didn’t know who he was, because Steven Spielberg wasn’t Steven Spielberg back then, you know? We talked about police work, and he wanted to see some of the locations where these things happened back in the ’60s, so I took him to a few.”

Specifically, Jurgensen took Spielberg to the sites of a series of murders in which gay men were slain by a pair of killers who impersonated cops. “I learned so much on ‘The French Connection,’ ” Jurgensen said, “and one of those things was that if a movie is based on reality and something that actually happened, let’s go and see where it went down. So Spielberg wanted to see where this all took place.”

Spielberg also wanted to know about police interrogation procedures. “He said, ‘How would you do this?’ and I put him up against a wall,” Jurgensen said. “I went top to bottom [frisking him], and I kept telling him, ‘Whatever the situation is, I must now be in control of it. I have to be in control.’ The way I’m saying that to you is the way I said it to Spielberg, and to this day he tells people I scared him during that interview!”

Even with all this first-hand preparation, Spielberg’s involvement with “Cruising” ended during the writing stage. “We just couldn’t come up with a script that met with my satisfaction,” D’Antoni said, “or even how to get around the mutilating of the genitals, which was such a big part of the original story. So we decided to abandon the project, and figured we’d go on to do something else together some other day, and Steven went back to LA.”

Given the filmography that followed, it’s hard to imagine Spielberg at the helm of a film involving genital mutilation, or the hardcore sexual material that initially got Friedkin’s “Cruising” slapped with an X rating. (“There might have been a shark running around in the damn club!” Friedkin joked in a 2013 Huffington Post interview.) Spielberg himself has never spoken publicly about his involvement with the project, but he’s better known for pushing the boundaries of PG with “Jaws” and “Indiana Jones and the Temple of Doom,” and while the director hasn’t hesitated to delve into the darker periods of our history — as in the unstinting wartime dramas “Schindler’s List” and “Saving Private Ryan” — his work is marked overall by a sense of hope and optimism regarding human nature.

Indeed, a more upbeat project based on a true-crime case would soon beckon him. About two months after Spielberg departed New York, D’Antoni got a phone call from producer Richard D. Zanuck, who had been running 20th Century Fox when D’Antoni began work on “The French Connection” there. “He and [producer] David Brown wanted to know about Spielberg,” D’Antoni recalled, “so I had lunch with David in New York. He said, ‘I know you were with him for about a month,’ and I told him Spielberg was terrific, and knew everything he wanted to do with ‘Cruising.’”

Shortly thereafter, D’Antoni read that Zanuck and Brown had hired Spielberg to make his big screen directorial debut on 1974’s “The Sugarland Express,” inspired by a real-life couple who led a lengthy police chase through Texas. “Not on my say-so alone; I’m sure 100 other things were involved. But it was a reconfirmation of Steve being such a nice guy as well as a talented kid.”

Sign Up: Stay on top of the latest breaking film and TV news! Sign up for our Email Newsletters here.