How Nazi investigators used secret tools to create Hitler’s Holocaust ‘hitlist’

New research reveals that paper conservators and manuscript restorers helped make centuries-old records legible for Nazi racial investigations, demonstrating how highly specialised crafts became entangled in the machinery of the Holocaust

Composite image showing a portrait of a Nazi leader overlaid with handwritten documents and a concentration camp entrance with railway tracks.

Published: February 24, 2026 at 3:19 PM

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It was SS officers and concentration camp guards who implemented and actualised much of the genocidal policy that had been crafted by senior Nazi officials. The SS, led by Heinrich Himmler, oversaw the police, the concentration camp system and many of the administrative structures that carried out the mass murder of Jewish populations and minority groups.

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These officers may have been the most visible architects of the Holocaust during the Second World War. But many historians have long argued that the systematic genocide levelled against Europe’s Jewish populations could never have reached the scale that it did without the complicity and active aid offered by ordinary people in everyday professions.

It was office administrators, clerks, railway workers and local officials whose work sustained the machinery of the Nazi state.

Now, new research has added more occupations to that list: bookbinders, paper conservators and restoration specialists.

According to findings by historian Dr Morwenna Blewett, first published in The Guardian, newly uncovered Nazi-era correspondence reveals a Europe-wide programme in which restorers repaired and chemically treated fragile archival documents so that they could be used to better trace Jewish ancestry. The work, she argues, helped Nazi authorities to compile genealogical records that functioned, in effect, as a bureaucratic “hitlist”.

Uncovering Jewish ancestry

In research that features in her upcoming book, Art Restoration Under the Nazi Regime, Blewett uncovered letters and administrative files showing how these expert restorers were recruited to clean and stabilise old church registers and civil records which documented local births, baptisms, marriages and religious conversions stretching back centuries.

Many of these manuscripts had become illegible through years of decay. Rather than preserving them in accordance with proper conservation standards, restorers used aggressive chemical treatments, including saturating pages with glycerine or laminating fragile sheets, to temporarily clean the documents and make them readable – even though these processes would destroy their long-term preservation.

Black-and-white photograph of men loading stacks of seized papers onto a truck under the supervision of uniformed Nazi officers.

During anti-Communist raids in 1930s Germany, Nazi authorities confiscated vast quantities of documents. The control of information through seizure, censorship, and meticulous filing became a central tool of Nazi power | Credit: Getty Images

Blewett’s research shows that Nazi officials described church books as an important source for proving Jewish descent, allowing the regime to determine who was considered Jewish under its racial laws.

By restoring these records, the conservators directly enabled the identification of people who would then be targeted for deportation and murder.

Dr Simone Gigliotti, a historian of the Holocaust and deputy director of Royal Holloway’s Holocaust Research Institute, says that the findings reinforce a broader historical understanding of how widely Nazi ideology penetrated professional life.

Speaking to HistoryExtra, she says Blewett’s research “confirms the fact that very few industries: bureaucratic, medical, cultural, economic, industrial or artisanal, were untouched by Nazi ideology. Neutrality in the arts and crafts industries was an illusion.”

The power of complicity

Blewett’s discovery also helps to clarify the precise mechanisms that underpinned the early stages of genocide.

Professor Christopher Browning is one of the world’s leading historians of the Holocaust. Speaking to HistoryExtra about the discovery, he says: “This new research does indeed illuminate the degree to which complicity in the Holocaust permeated even the most obscure professions in Germany. Historians have known this in principle, but not this particular example.”

Dr Gigliotti similarly emphasises how deeply professional complicity extended beyond institutions of the Nazi state. “[Professional complicity] was very extensive, indeed, embedded into German society,” she explains.

Black-and-white photograph of Nazi soldiers confronting a line of Jewish civilians in the Warsaw Ghetto during the Second World War.

Soldiers question Jewish residents during the suppression of the Warsaw Ghetto Uprising in 1943, a moment enabled by an immense bureaucratic system. The Holocaust depended on administrative compliance woven throughout institutions and occupied societies | Credit: Getty Images

For the Nazis, the importance of tracing Jewish ancestry emerged after the Nuremberg Laws. Introduced in 1935, these laws stripped Jews of German citizenship and prohibited marriage or sexual relationships between Jews and so-called ‘Aryans’.

Professor Browning explains: “Raul Hilberg, one of the founders of Holocaust studies, wrote in 1961 that the first major step in the Holocaust was the definition of the victim. The Nuremberg Laws defined ‘full’ Jews as having three or four Jewish grandparents, and so-called ‘Mischlinge’ [meaning ‘mixed bloods’] as having one or two Jewish grandparents.”

This was a determination that required documentary proof. Because Germany lacked a unified national registry before the late 19th century, these records were scattered across thousands of local churches and synagogues. In many regions, especially in rural areas, parish records stretching back to the 17th or 18th centuries were the only surviving documentation of family lineage.

Professor Browning says: “For the Nazi bureaucracy to determine who was a Jew, or for individuals to document their ancestry as ‘free of Jews’, genealogy businesses sprang up to research old church and synagogue records. What this new research shows is that this, in turn, spawned an additional new business: the cleaning of these old records to make them readable.”

The bureaucratic obsession with documentation, however, was not universal across Europe. Browning notes that such painstaking genealogical classification primarily applied to German Jews. In eastern Europe, where most Holocaust victims lived, “no one worried about the details of legal documentation to this degree.”

“Being identified as Jewish by one’s neighbours or being suspected of being Jewish by appearance was sufficient to be killed,” he says.

WATCH | Laurence Rees explains how the Nazis governed Germany in the 1930s

Creating a racial hierarchy through genealogy

The German reliance on archival records also underlines a deeper contradiction at the heart of Nazi racial ideology. While the regime tried to extol a claim of scientific rationale behind its racial hierarchy, it ultimately depended on paperwork rather than biology.

Professor Dan Stone, director of the Holocaust Research Institute at Royal Holloway, says Blewett’s findings reinforce a wider understanding of how central genealogy became to Nazi policy. Speaking to HistoryExtra about the research, he explains why it's not surprising that old ancestry documents became such a decisive tool.

“Because the Nazis couldn’t identify such a thing as a ‘Jewish race’ through scientific means (because no such thing exists), their definition of Jews as being people with Jewish grandparents meant that genealogical, as opposed to anthropological or biological, factors were crucial.”

“The emotional pull of ‘thinking with the blood’ overrode any scientific findings about the complexity of race,” he says.

Dr Gigliotti notes that this bureaucratic fixation produced one of the defining administrative features of the Holocaust: lists. “The Holocaust and its lists are inseparable,” she explains.

“Lists of Jewish people selected for deportation, Jewish refugees waiting for visas but denied, Jewish deportees listed as having arrived at concentration camps, Jewish passengers appearing on shipping lists, and finally, that most consequential of lists, the Wannsee Conference list of Jewish communities across the world and their numbers by country. Lists classify, separate and isolate.”

Professor Stone agrees that it was this level of organisation that was fundamental in turning abstract Nazi ideology into concrete action.

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"That there was a bureaucracy tasked with identifying the relevant genealogical records, both to prove who was a Jew and to adjudicate on claims for ‘Aryan status’, makes perfect sense.”

Authors

James OsborneSenior content producer

James Osborne is a senior content producer at HistoryExtra

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