Coverage of Douglas’s case was predictably slanted: The word “rape” was deemed unfit to print, so front-page newspaper articles resorted to euphemisms like “ravished.” And while her home address was widely published, M.G.M. — the world’s best-known purveyor of Hollywood product and largest employer in Los Angeles County — was identified only as “a local film studio.”

M.G.M. may have seemed its invincible self, but behind the scenes there was panic. “Gee whiz, Louis,” fretted the media baron (and movie producer) William Randolph Hearst to Mayer in a letter about the party recently discovered in Hearst’s private archive and quoted here for the first time, “do you realize how damaging that is to the whole moving picture industry and fraternity?”

“I am going to do everything I can now to help this situation, of course,” promised Hearst. “But the public will be sympathetic with a poor little extra girl.”

Douglas gave no interviews, letting her lawsuit speak for itself. Meanwhile M.G.M. unleashed a smear campaign: Pinkerton detectives subjected her to surveillance; pressured her doctor to falsely say she had gonorrhea; and strong-armed fellow dancers to sign statements tagging her a promiscuous drunk. (In our own era, Harvey Weinstein would follow his forebears, hiring outside help to besmirch accusers.)

A Los Angeles County judge dismissed Douglas’s suit. Yet again she could have given up; instead the next day she refiled in United States District Court. For the first time in our nation’s history, a woman made rape a federal case by invoking its violation of her civil rights.

Douglas used every legal resource available to her, but a young dancer was no match for M.G.M., which best evidence shows now bought off her mother, the court-appointed guardian in her lawsuit. Blackballed by the studios, shunned as “damaged goods,” Douglas disappeared without a trace, spending the rest of her life in seclusion. “We had her killed,” I was told Mannix wisecracked. So thoroughly did M.G.M. expunge Patricia Douglas from the historical record that when I first stumbled upon her story, no reference source whatsoever cited her case, while a Google search of her name yielded nothing.