Nazi hunters are investigators who track down former members of the Nazi regime and their collaborators who committed war crimes during World War II, then build the evidence needed to prosecute, extradite, or deport them. Some work for governments; others operate through private organizations funded by survivors and donors. Their methods combine archival research, witness testimony, and a specialized body of international law that treats genocide and crimes against humanity as crimes without a time limit. More than a hundred successful court actions have come out of their work since 1945.
Why the Work Was Necessary
In the collapse of 1945, tens of thousands of former SS members, camp guards, and collaborators discarded their uniforms and disappeared into the flood of displaced persons moving across Europe. Many used escape routes that investigators later called “ratlines,” which generally ran from Germany or Austria through Italy and on to South America, the Middle East, or other places beyond Allied reach.
Those routes depended on documents and shelter. Certain Catholic clergy, most prominently Bishop Alois Hudal in Rome, supplied forged identity papers and hiding places in monasteries. With those papers, fugitives could obtain travel documents from the International Committee of the Red Cross, which at the time had limited ability to verify who was applying. Argentina received the largest share, with Brazil, Chile, Paraguay, and Syria also harboring significant numbers. Adolf Eichmann, the chief logistical architect of the Holocaust, reached Argentina with the help of a Franciscan monk. Josef Mengele, who conducted medical experiments on Auschwitz prisoners, took the same Italian corridor.
The picture was complicated by the United States itself. Operation Paperclip, which ran from 1945 to 1959, recruited more than 1,600 German scientists and engineers, many with Nazi records, for American weapons work and to keep them out of Soviet hands. Some of the same government that was supposed to pursue war criminals was quietly importing others.
The People Who Made Nazi Hunting a Vocation
Simon Wiesenthal
Simon Wiesenthal survived multiple concentration camps, including Mauthausen, where he was liberated in May 1945. Two years later he founded the Jewish Historical Documentation Center in Linz, Austria, and spent the rest of his life collecting evidence for war crimes trials. He helped identify and locate Eichmann; found Karl Silberbauer, the Gestapo officer who arrested Anne Frank, in 1963; tracked Franz Stangl, the commandant of Treblinka, to Brazil in 1967; and located Hermine Braunsteiner, a former camp guard, living in Queens, New York, in 1973. He worked until shortly before his death in 2005. The Simon Wiesenthal Center, founded in Los Angeles in 1977, continues the work.1Simon Wiesenthal Center. Simon Wiesenthal
Serge and Beate Klarsfeld
Serge Klarsfeld, whose father was deported from France to Auschwitz and killed there, worked with his wife Beate to document all 76,000 Jews deported from France during the occupation. Together they tracked Klaus Barbie, the Gestapo chief of Lyon, and pushed for his extradition from Bolivia to France. They survived two assassination attempts, suffered beatings, and were arrested after attempting to abduct a former Gestapo chief in Germany. Their evidence also supported convictions of other former Nazis and French collaborators.
Efraim Zuroff and Eli Rosenbaum
Efraim Zuroff, the chief Nazi hunter for the Simon Wiesenthal Center, runs Operation Last Chance, which offers cash rewards for information leading to the arrest of remaining suspects. Eli Rosenbaum spent 40 years at the U.S. Department of Justice pursuing Nazi war criminals in the United States and recorded 119 court victories, more than all other countries combined during the same period. In 2022 he was asked to lead a DOJ team prosecuting war crimes committed in Ukraine.
How a Case Gets Built
The work begins in archives. Investigators comb through surviving personnel files from the SS, Gestapo, and other organizations. Records for more than 61,000 SS officers survived the war and are held by the U.S. National Archives.2National Archives. Berlin Document Center Series 6400: SS Officers Service Records Those files are cross-referenced against immigration records, displaced persons documents, and Red Cross travel applications to see whether a suspect obtained new papers under a false name.3United States Holocaust Memorial Museum. Holocaust Survivors and Victims Database A small variation in a surname, a mother’s maiden name used as an alias, or an unexplained gap in a work history can be the first thread.
Witness testimony has always carried the human weight of these cases. Survivors who recognized a face, remembered a regional accent, or could describe a specific act of violence gave investigators what paper could not. Those accounts were matched against service records to place a suspect at a particular camp during a particular period. Genealogical databases helped when a suspect had changed names entirely.
A finished dossier tracks a person across countries and decades. It looks for family members who moved to the same city, bank accounts linking back to a prior identity, and naturalization applications that leave out wartime service. All of this intelligence work happens before law enforcement is involved. The completed file usually includes military service records, immigration applications, and witness statements that place the suspect at specific crimes.
Technology has sped the work considerably. The Arolsen Archives, formerly the International Tracing Service, now hold more than 40 million digitized documents on Nazi persecution, searchable online.4Arolsen Archives. International Center on Nazi Persecution DNA testing can confirm the identity of someone who has lived under an alias for seventy years.
The Legal Tools That Make Late Prosecution Possible
Three legal principles have kept Nazi cases viable long after the war.
The first is universal jurisdiction, which allows any country’s courts to prosecute the most serious international crimes regardless of where they happened or the nationality of the perpetrator.5Office of the United Nations High Commissioner for Human Rights. What is Universal Jurisdiction By 2012, 163 countries had laws permitting some form of universal jurisdiction, and by 2021, 125 international criminal charges had been brought under the principle across 16 countries.
The second is the absence of a statute of limitations. The 1968 UN Convention on the Non-Applicability of Statutory Limitations to War Crimes and Crimes Against Humanity codified the rule that no time limit applies to genocide, war crimes, or crimes against humanity.6Office of the United Nations High Commissioner for Human Rights. Convention on the Non-Applicability of Statutory Limitations to War Crimes and Crimes Against Humanity
The third is denaturalization. In the United States, constitutional limits block criminal prosecution for crimes committed abroad before World War II, so prosecutors bring civil cases to strip citizenship from people who lied about their wartime activities on naturalization applications.7United States Department of Justice. Office of Special Investigations If an immigration interview concealed service in a killing unit, citizenship was obtained by fraud and can be revoked. Deportation follows. The Office of Special Investigations, created inside the Justice Department in 1979, won cases against 101 participants in Nazi crimes against humanity over 25 years, a total that exceeded every other government in the world combined during that period.
A fourth development reshaped German prosecutions in the twenty-first century. For decades German courts required a direct link between a specific defendant and a specific killing before they would convict for accessory to murder. Low-ranking guards usually escaped charges on that ground. That changed with the 2011 conviction of John Demjanjuk, a former guard at Sobibor. A German court accepted the argument that serving at a facility whose sole purpose was mass murder made a guard an accessory to the killings that occurred there.8United States Holocaust Memorial Museum. John Demjanjuk: Trying a Nazi Collaborator Prosecutors have used the same theory since. Oskar Gröning, the “bookkeeper of Auschwitz,” was sentenced to four years in 2015. Josef S. was convicted at 101 on more than 3,500 counts of accessory to murder for guarding Sachsenhausen and sentenced to five years. Accessory to murder under German law carries three to fifteen years, which is why these sentences read as short.9Zentrale Stelle Ludwigsburg. Criminal Acts
Landmark Cases
Adolf Eichmann
Eichmann coordinated the logistics of deporting millions of Jews to death camps and escaped to Argentina under a false name. In May 1960 a team of Israeli Mossad agents, operating under Mossad chief Isser Harel with the backing of Prime Minister David Ben-Gurion, seized him near his home outside Buenos Aires.10Yad Vashem. Eichmann Was Captured in Argentina on 11 May 1960 After he admitted his identity and signed a document consenting to trial in Israel, he was flown out on an El Al airliner eleven days later. He was tried in Jerusalem under Israel’s 1950 Nazi and Nazi Collaborators’ Punishment Law, convicted on 15 counts, sentenced to death on December 15, 1961, and hanged on June 1, 1962.11United States Holocaust Memorial Museum. Eichmann Trial
Klaus Barbie
Barbie, the Gestapo chief in Lyon, was responsible for the torture and deportation of thousands, including the children of Izieu, a group of Jewish children hidden in a farmhouse who were rounded up and sent to Auschwitz. In 1971 the Klarsfelds identified him in South America, living as Klaus Altmann. His protection from the Bolivian military shielded him for years. When that regime fell he was arrested in 1983, returned to France, and in 1987 convicted of crimes against humanity and sentenced to life in prison.12United States Holocaust Memorial Museum. Klaus Barbie: The Butcher of Lyon
Where Things Stand Now
Age is the limit the work cannot overcome. Anyone who held a meaningful role during the war would be at or past 100 by 2026. Among those charged in the twenty-first century, many have died awaiting trial, during appeals, or before imprisonment. Few have served real time, and the sentences that have been imposed are largely symbolic. In 2023, German prosecutors charged a 100-year-old former camp guard with aiding and abetting murder in more than 3,300 cases; proceedings were initially suspended for the defendant’s frailty before a higher court allowed the case to continue.
The Simon Wiesenthal Center still maintains its list of remaining suspects and runs Operation Last Chance, which offers up to $25,000 for information leading to the arrest and conviction of former Nazis who served in death camps or mobile killing squads.1Simon Wiesenthal Center. Simon Wiesenthal The U.S. Holocaust Memorial Museum has observed that nearly all perpetrators have died and that only a small minority will ever have been brought to justice.13United States Holocaust Memorial Museum. The Search for Perpetrators
What outlasts the hunters is the legal machinery they helped create. Universal jurisdiction, the rejection of time limits for atrocity crimes, and the cog-in-the-machine doctrine all came out of or were strengthened by Nazi cases. Those same tools are now used against perpetrators of genocide in Rwanda, ethnic cleansing in the former Yugoslavia, and war crimes in Syria and Ukraine. The Justice Department unit that began as the Office of Special Investigations now operates as the Human Rights and Special Prosecutions Section, applying the same framework to modern atrocity crimes.14United States Department of Justice. Human Rights and Special Prosecutions Section