Jakob Reimer’s Trawni­ki iden­ti­fi­ca­tion card pho­to, tak­en by the SS. Image cour­tesy of the U.S. Depart­ment of Justice.

Young Peter Black was some­thing of a lon­er, con­tent to spend long after­noons read­ing about the move­ment of armies, the slow, plain­tive notes of the Five Satins play­ing on a suit­case turntable, and a dog-eared copy of The Rise and Fall of the Third Reich sit­ting on his night­stand. He played wif­fle ball in the dri­ve­way and pick­up foot­ball games in a field behind the high school. But it was his­to­ry that moved him, kept him awake at night next to a stack of Mad mag­a­zines and com­ic books that at times seemed awful­ly sil­ly, giv­en how war could turn ordi­nary peo­ple into mur­der­ers. This was the 1950s, in a qui­et neigh­bor­hood in the sub­urbs of Boston.

Peter Black, now retired, ded­i­cat­ed years to the OSI. Image cour­tesy of U.S. Holo­caust Memo­r­i­al Museum.

One day in mid­dle school, Black decid­ed he would study the his­to­ry of Nazi Ger­many. By the time he enrolled at the Uni­ver­si­ty of Wis­con­sin in 1968, Adolf Hitler had been dead for twen­ty-three years. But to Black, the need to under­stand the deci­sions of nation­al lead­ers bent on mass mur­der seemed more urgent than ever, con­sid­er­ing a world that had stum­bled into a nuclear age.

I met Black in the ear­ly months of 2017. By then, he had spent his pro­fes­sion­al career doing exact­ly what he had vowed to as a teen — and to great suc­cess. As a World War II his­to­ri­an, he had been part of a tiny unit deep inside the U.S. Depart­ment of Jus­tice that for more than three decades iden­ti­fied and pros­e­cut­ed Nazi war crim­i­nals who slipped into the Unit­ed States along­side mass­es of Euro­pean refugees in the years after the war.

Since 1990, the Office of Spe­cial Inves­ti­ga­tions (OSI) helped denat­u­ral­ize and deport more than sev­en­ty Nazi col­lab­o­ra­tors — more than all oth­er coun­tries in the world com­bined, includ­ing Germany.

As a vet­er­an inves­tiga­tive reporter, I had spent a decade on staff at The Wash­ing­ton Post. But I knew very lit­tle about the Nazi-hunt­ing unit, or the men and women who raced against time to expose and bring to jus­tice war crim­i­nals hid­ing in plain sight in mid­dle-class Amer­i­ca — their ter­ri­ble secrets buried deep.

I came away from that first meet­ing with Black with two ques­tions. In a coun­try that had sac­ri­ficed so much to defeat Hitler and save the Jews of Europe, how was it pos­si­ble that Hitler’s helpers were liv­ing here along­side Holo­caust sur­vivors and vet­er­ans who had crossed an ocean to free them?

Eliz­a­beth Bar­ry” White, cur­rent­ly a his­to­ri­an at the U.S. Holo­caust Memo­r­i­al Muse­um, spent years work­ing at the OSI. Image cour­tesy of U.S. Holo­caust Memo­r­i­al Museum.

And just as intrigu­ing: How did Black and his col­leagues man­age to probe some of the war’s dark­est moments, day after day, year after year, and then free them­selves from that dark­ness when they went home at night, when it came time to have din­ner with a spouse, rock a new­born, coach a soc­cer game, take an anniver­sary trip?

By the time I fin­ished writ­ing Cit­i­zen 865: The Hunt for Hitler’s Hid­den Sol­diers in Amer­i­ca, I dis­cov­ered the sto­ry was not just about dark­ness but also about light, the pur­suit of truth by Black and a team of Amer­i­can Nazi hunters who believed that jus­tice — even delayed — is more crit­i­cal than ever in a world that too often finds itself in the exact same place, con­front­ed by big­otry, hate, mass murder.

Cit­i­zen 865 is focused on a less­er-known inves­ti­ga­tion car­ried out by the OSI: the hunt for the men of Trawni­ki. In 1990, in a dusty base­ment archive in Prague, Black and OSI his­to­ri­an Eliz­a­beth Bar­ry” White dis­cov­ered a Nazi ros­ter from 1945 that no West­ern inves­ti­ga­tor had ever seen. The long-for­got­ten doc­u­ment, con­tain­ing more than 700 names, helped unrav­el the details behind a lethal killing force that had helped the SS mur­der 1.7 mil­lion Jews in few­er than 20 months, the span of two Pol­ish sum­mers. Ear­ly in the war, the men had trained at a camp in the Pol­ish vil­lage of Trawniki.

It was, in every sense, an SS school for mass murder.

Over many months, I essen­tial­ly retraced the steps of Black and the OSI team. I trav­eled to Trawni­ki, Prague, War­saw, Lublin and Vien­na, pored over war records and court tran­scripts and stud­ied the oral his­to­ries of Holo­caust wit­ness­es and sur­vivors. Some had set­tled in the Unit­ed States after the war only to learn that the so-called Trawni­ki men” had fol­lowed — and gone on to become nat­u­ral­ized citizens.

The OSI team pur­sued these men, and, up against the forces of time and polit­i­cal oppo­si­tion, bat­tled to the present day to remove them from US soil.

Peter, Bar­ry, and two oth­er his­to­ri­ans in Prague in 1990. Image cour­tesy of Bar­ry White.

Even after Black went on to work at the Unit­ed States Holo­caust Memo­r­i­al Muse­um, he con­tin­ued to work on Trawni­ki cas­es. Over time, he helped iden­ti­fy more than 5,000 mem­bers of the killing force, becom­ing the world’s fore­most expert on the camp and its recruits.

If legal con­se­quences for mass mur­der and mass atroc­i­ty become habit­u­al to polit­i­cal and judi­cial behav­ior in the twen­ty-first cen­tu­ry,” Black said after his retire­ment, per­haps we can pre­vent mass mur­der in the future.”

I found hope in Black’s words and in the stead­fast work of a deter­mined team of his­to­ri­ans and pros­e­cu­tors who refused to look away.

Deb­bie Cen­ziper is an inves­tiga­tive jour­nal­ist, pro­fes­sor, and author based in Wash­ing­ton, D.C. A con­tribut­ing reporter for the inves­tiga­tive team at The Wash­ing­ton Post, she has won many major awards in print jour­nal­ism, includ­ing the 2007 Pulitzer Prize. Cen­ziper is the co-author of the crit­i­cal­ly acclaimed Love Wins: The Lovers and Lawyers Who Fought the Land­mark Case for Mar­riage Equal­i­ty. She was recent­ly named the direc­tor of inves­tiga­tive jour­nal­ism at the North­west­ern Uni­ver­si­ty Medill School of Journalism.