“I stood there for 15 minutes reading it over and over again,” Hegness said of the letter by the author of “The Jungle,” the groundbreaking 1906 book that exposed unsanitary conditions at slaughterhouses. The last paragraph got the Newport Beach attorney’s attention. “This letter is for yourself alone,” it read. “Stick it away in your safe, and some time in the far distant future the world may know the real truth about the matter. I am here trying to make plain my own part in the story.” The story was “Boston,” Sinclair’s 1920s novelized condemnation of the trial and execution of Nicola Sacco and Bartolomeo Vanzetti, Italian immigrants accused of killing two men in the robbery of a Massachusetts shoe factory.

Prosecutors characterized the anarchists as ruthless killers who had used the money to bankroll antigovernment bombings and deserved to die. Sinclair thought the pair were innocent and being railroaded because of their political views. Soon Sinclair would learn something that filled him with doubt. During his research for “Boston,” Sinclair met with Fred Moore, the men’s attorney, in a Denver motel room. Moore “sent me into a panic,” Sinclair wrote in the typed letter that Hegness found at the auction a decade ago. “Alone in a hotel room with Fred, I begged him to tell me the full truth,” Sinclair wrote. ” …

He then told me that the men were guilty, and he told me in every detail how he had framed a set of alibis for them.” Hegness paid $100 for the box containing Sinclair’s confessional letter and tucked it away in a closet — where it gathered dust. Now, after stumbling upon it again, he plans to donate it to Sinclair’s archives at Indiana University, where it will join a trove of correspondence that reveals the ethical quandary that confronted Sinclair — papers that even some scholars of the author weren’t aware of. “This is a stunning revelation,” said Anthony Arthur of Los Angeles, a retired literature professor and author of the recently released biography, “Upton Sinclair: Radical Innocent.” “I’ve never heard of this,” added Lauren Coodley, a professor of history and psychology at Napa Valley College who edited a recent Sinclair anthology. “It’s one of those amazing things.

That’s why history is so fascinating, because we keep revising it.” Upton Beall Sinclair was a giant of the nation’s Progressive Era, a crusading writer and socialist who championed the downtrodden and persecuted. President Theodore Roosevelt, who pushed through the nation’s first food-purity laws in response to “The Jungle,” coined the name for Sinclair’s craft: muckraker. Sinclair wasn’t alone in believing Sacco and Vanzetti were innocent when he began researching the book that fictionalized their case.

On Aug. 23, 1927, the day they were executed, 25,000 protested in Boston. The men have been viewed as martyrs by the American left ever since. Historians agree that prosecutors in the case were biased and shoddy, and that the two men failed to receive a fair trial. On the 50th anniversary of their execution, Massachusetts Gov. Michael S. Dukakis all but pardoned the pair, urging that “any disgrace should be forever removed from their names.” But the fearless Sinclair was left a conflicted man by what Sacco and Vanzetti’s lawyer — and later others in the anarchist movement — told him. “I faced the most difficult ethical problem of my life at that point,” he wrote to his attorney. “I had come to Boston with the announcement that I was going to write the truth about the case.”

Other letters tucked away in the Indiana archive illuminate why one of America’s most strident truth tellers kept his reservations to himself. “My wife is absolutely certain that if I tell what I believe, I will be called a traitor to the movement and may not live to finish the book,” Sinclair wrote Robert Minor, a confidant at the Socialist Daily Worker in New York, in 1927.”Of course,” he added, “the next big case may be a frame-up, and my telling the truth about the Sacco-Vanzetti case will make things harder for the victims.”

He also worried that revealing what he had been told would cost him readers. “It is much better copy as a naïve defense of Sacco and Vanzetti because this is what all my foreign readers expect, and they are 90% of my public,” he wrote to Minor.

ADVERTISEMENT Sinclair was born in 1878, and his upbringing in New York City was framed by his parents’ poverty and his grandparents’ wealth. He entered college at 14 and paid for school by writing stories for newspapers and magazines. His first novel was published in 1901. He moved to Southern California in 1915. In 1926, he ran as a Socialist for California governor, getting 60,000 votes. He took another stab in 1934, during the Great Depression, this time winning the Democratic primary with a platform of ending poverty. He got nearly 900,000 votes. In 1943, Sinclair won a Pulitzer Prize for “Dragon Teeth,” a novel that dealt with Hitler’s rise to power. He died in a small town in New Jersey in 1968 at the age of 90, having never publicly disclosed his doubts about the innocence of Sacco and Vanzetti. Ideale Gambera, whose father was a Boston anarchist in the 1920s, said he could empathize with Sinclair’s angst about revealing his doubts. Gambera, 80, said there was a strict code of silence to protect the group and hide the nature of their activities. He said his father, Giovanni Gambera, a member of the Sacco-Vanzetti Defense Committee, told him before he died in 1982 that Sacco was one of the killers. “They all lied,” said Gambera, a retired English professor living in San Rafael. “They did it for the cause.” *