That’s William J. Flynn standing there in the dapper hat and trenchcoat. Back in 1919, he was very hot stuff. They called him “Big Bill,” the most famous detective in America, former chief of the U.S. Secret Service, former top gumshoe in New York City, recognied as the country’s top spy catcher, Red hunter, counterfeit tracker, enemy of gangsters, kidnappers, bank robbers, gamblers, and criminals of every type.

You could barely pick up a newspaper in the 1910s without seeing his name. He loved splashy midnight raids, and helped terrify the country against German saboteurs during World War I. In his spare time, he even wrote detective novels, mostly making himself the hero.

In 1919, Flynn landed in Washington, D.C. The Attorney General, A. Mitchell Palmer, asked him, begged him, to leave New York and become the new Director of the Justice Department’s Bureau of Investigation (later renamed the FBI). Flynn would hold the job for two years. One of his lieutenants would be a skinny young kid named J. Edgar Hoover who later would head the FBI for 48 years, the most controversial law enforcement figure in Twentieth Century America.

Depite all his big headline-grabbing cases, nobody much remembers Bill Flynn these days. But that could change. A new movie is being made about Flynn’s Justice Department days that, if done right, could nicely poke a rarely-exposed sensitive raw nerve in the American past.

Mitchell Palmer had a special job in mind for Flynn when he invited him to come to Washington in 1919 and head the Bureau of Investigation. Palmer intended to launch a massive crackdown against subversives — communists, anarchists, labor radicals, and a few truly dangerous people — that would culminate in one of the worst civil liberty abuses in American history. Between late 1919 and early 1920, Justice Department agents, working with local police and vigilantees, rounded up some 10,000 people, locked them in overcrowded prisons, had them beaten, abused, cut off from lawyers, threatened with deportation, and then, months later, the large majority simply released, never accused of a crime. The reason? A massive case of paranoia and guilt by association known as the First Red Scare.

Flynn’s direct role in this affair has always been a mystery. Palmer himself and young Hoover played the visible leads — hence the “Palmer Raids”– but Flynn was the person actually in charge of the Bureau at the time. I tell the story of the Raids from Hoover’s point of view in my book Young J. Edgar: Hoover, the Red Scare, and the Assault on Civil Liberties. Now it’s time for Flynn’s.

The new movie, called No God, No Master, recently began shooting in Milwaukee, Wisconsin, (which has several streets that look like 1919 New York City). To play Flynn, it casts actor David Strathairn — who played Edward R. Murrow in the 2005 George Clooney film Good Night, and Good Luck. The production team describes the story this way:

“No God, No Master is the story of U.S. Bureau of Investigation agent William Flynn who is swept into the world of homegrown terrorism during the Red Scare of the early 1900s. His journey into the culture of anarchism sets the stage for a timely drama with rsounding parallels to the politics and issues of contemporary society.”

Let’s hope they do a good job. This is an important story, full of lessons clearly forgotten during the hysteria of our own generation’s War on Terror following the attacks on our country of September 11, 2001. Too often, movies get it wrong. I have my fingers crossed that this will be the exception.