In an early scene of the 1948 film Call Northside 777, Jimmy Stewart, who plays a reporter at the Chicago Times, interviews a scrubwoman who placed a classified ad (how quaint!) in the paper offering a $5,000 reward for information leading to the exhoneration of her son, who is serving ninety-nine years in prison for killing a cop. The scrubwoman says she saved her pennies for ten years to raise the reward money, and she asks Jim McNeil, Stewart’s character, if he can help her. He replies: “I’m only a reporter. I just write the story.”

That humble schtick lasts about fifteen minutes. Soon enough, McNeil is convinced—by his good-hearted editor, his puzzle-obsessed wife, and his own conscience—that the scrubwoman’s son, Frank Wiecek, is indeed innocent. He embarks on a crusade to prove it, in which he blithely violates some of journalism’s most sacred ethical tenets: he plays up aspects of Wiecek’s story calculated to elicit public sympathy, and ignores those that may do the opposite; he tries to cut a deal with Wiecek’s co-defendant, the alleged trigger-man, to say who was really with him the night of the murder in exchange for the Times’s support in getting the man parole; he poses as a cop to get access to Wiecek’s arrest file; he poses as a family friend to find the witness who fingered Wiecek. (The most irritating thing about McNeil, though, is that he never takes notes—ever.)

The audience, and the critics, cheered him on. The reviews at the time took no interest in the ways and means of the reporter, focusing instead on the pros and cons of the then-novel “documentary style” of filmmaking. (Call Northside 777 was based on a true story, but more on that later.)

This pass on the ethics isn’t really surprising. Traditionally, Hollywood’s portrayal of the press has tended to reflect the public’s attitudes. And though it’s hard to imagine today, when journalists often appear on the big screen as callous scumbags who gleefully invade our privacy to advance their careers, Call Northside 777 was made in an era when the public viewed journalists a bit more generously. “In the 30s and 40s, people loved reporters—they were cynical and tough and hard-edged, and that made for comedy and good lines,” the late critic Pauline Kael told The New York Times in 1997. Back then, too, journalists were typically played by beloved stars, like Stewart and Cary Grant and Humphrey Bogart, and audiences would indulge all manner of unsavory behavior in the characters these actors portrayed.

It’s worth noting, also, that this was a period when journalists were much more of the people, so to speak, than they are today. Journalism had not yet become a profession, the barriers to entry were lower, as were the educational requirements. McNeil isn’t some Ivy-League dandy (his well-fitting suits notwithstanding), but a regular guy who is as at home canvassing the seedy bars by the stockyards as he is meeting with representatives from the governor’s office—maybe more so. At the end of the film (spoiler alert!), when Wiecek leaves prison and McNeil is there to greet him, McNeil says, “It’s a big thing when a sovereign state admits an error. Remember this: there aren’t many governments that would do it.” Sure, it was 1948 and this is standard cold-war rhetoric. But it also reflects a common man’s feelings about his government in the wake of World War II, at the dawn of the nuclear age, and the emergence of a bipolar world—not the cynical view of a hotshot.

In the post-Watergate era, the job, and the business, changed. Journalists became heroes and celebrities, the job became aspirational and increasingly its practitioners identified upward. Reporters joined the professional class, and their newsrooms became part of huge corporations. Soon, to the great mass of people, journalists became The Other, part of the elite, the establishment.

But when I came across a document on the website of the Center for Wrongful Convictions at Northwestern University’s Law School, however, my understanding of how Hollywood treated this slice of journalistic history changed. Remember, Call Northside 777 is based on a true story, and here we have a detailed account of what actually happened.

Brent Cunningham is CJR’s managing editor.