One doesn’t traditionally think of gangsters, secret agents and G-men when contemplating the murky world of Nazi espionage but they all come into play in Peter Duffy’s dramatic new investigation Double Agent, a nonfiction account that explores one of the 20^th century’s most successful turncoats. In a story so dramatic it sounds as if it should be fiction, Duffy (The Killing of Major Denis Mahon, 2008, etc.) resurrects one William G. Sebold, a German-American engineer who was approached by representatives from German military intelligence in 1939 and encouraged to spy for the Nazis in his new home, the United States of America. But the Nazi war machine vastly underestimated the naturalized American citizen, who became the FBI’s very first “double agent.”

“I was doing some research and I began to become interested in Fifth Column activity in the United States, particularly Nazi or Fascist activity leading up to World War II,” says Duffy in explaining the origins of this peculiar spy tale. “In looking into that history, I stumbled across this huge spy bust and was really quite surprised it hadn’t been written about in any extensive way. It was mentioned in a few pulpy spy books in the 1940s and was the basis for a 1945 film (The House on 92^nd Street), but that was it. It was this huge espionage bust where a single individual, William Sebold working as a double agent, was responsible for the takedown of an entire network of enemy spies.” 

That network is colloquially known as the Duquesne Spy Ring and is named for its leader, a flamboyant South African raconteur named Fritz Duquesne. Together with a wide range of dubious characters, the ring collected information on a variety of American enterprises including the development of a new bomb sight, with the intention of transmitting the data back to Berlin.

“One of the things I find most fascinating about New York City in the 1930s is that there were something like 350,000 German and Austrian-born residents of New York,” Duffy observes. “By way of comparison, there are about 350,000 Chinese-born residents of New York currently, so it’s a significant population with large German neighborhoods with residents carrying a variety of political points of view. Many Germans came to the country during the Weimar years, carrying with them the predisposed ideological positions that would later fuel the Nazi rise to power. In order to recruit members of the community who were willing to commit acts of espionage on behalf of the Reich, you really have to have the population to create a spy ring of this size.”

However, the Nazis dramatically underestimated the mild-mannered Sebold, who immediately approached the U.S. Consulate and was subsequently recruited as a double agent for the F.B.I.

“Double agents are so often individuals who are compromised in some way,” Duffy says. “They’re generally people who have been caught doing something wrong and they have to act to rectify their situation with the authorities. Sebold is this rare case where he is coerced by the Nazis, but doesn’t perform any activity on behalf of the Germans and almost immediately engages with the F.B.I. “

Much of the information in Double Agent comes from the diaries of Sebold’s government handler, a special agent named Jim Ellsworth.

“Ellsworth is really a remarkable character in that he’s not really the cinematic G-man,” Duffy explains. “He is this all-American, very religious, very upstanding agent. If you had the misfortune of getting the attention of the F.B.I., Jim Ellsworth would be the guy you want investigating your case, because he was so honest and upright.” 

Strangely, the story even shares some characters with Bryan Burrough’s excellent gangster epic Public Enemies, as one of the lead agents on the case was Earl J. Connelley, the special agent who had also pursued John Dillinger and led the Florida raid on “Ma” Barker’s hideout earlier in the decade.

“It’s never thought of as the same era,” Duffy admits. “The Prohibition-era gangsters really feel like a pre-war phenomenon. They feel like two different eras when in fact they were fairly close together. These were the same people investigating these espionage cases.”

On the 13^th of December, 1941—barely days after Germany declared war on the United States—33 members of the Duquesne Spy Ring were convicted of espionage. Duffy admits that we will never know the scope of the potential damage that was undone by William Sebold. But he points to the 1942 capture of eight Nazi saboteurs in 1942 who were delivered by U-boats—“…a farcical mission that was made necessary by the conviction of so many potential bomb-planters in the Sebold case. 

“The case of those U-boats was a pretty obvious acknowledgement that the busts in the Duquesne case left the Nazis without any reliable in-country intelligence,” he says. “If somebody like Fritz Duquesne, despite all his grandiosity, was left unmolested through 1942 with a clear connection to Germany, who knows what he could have accomplished?”

As for Sebold, who died in obscurity at Napa State Hospital in 1970 after a long struggle with mental illness, Duffy believes he deserves more acclaim.

“You never know what a person will do when they’re pushed up against the wall,” Duffy says. “I think that William Sebold really exemplifies an ordinary person being forced into a position he never could have foreseen during a time of genuine crisis, and really coming through. I hope they name a water fountain or something after him at the F.B.I.”