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From an Attic in Amsterdam to a Raid in Argentina: How One Dutchman’s Discovery Exposed a Nazi-Looted Painting

By: Fern Sidman

When 74-year-old Dutch systems specialist Paul Post climbed into his late mother’s attic fifteen years ago, he thought he was merely sorting through family keepsakes. Instead, as Reuters and The Algemeiner reported on Saturday, he unearthed a historical mystery that would span continents, bridge generations, and culminate in the arrest of a Nazi official’s daughter in Argentina.

At the heart of the story lies a rediscovered set of wartime notebooks — his father’s Nazi-era diaries — which detailed life under occupation in the Netherlands. Within their yellowing pages, Post stumbled upon the name of a man whose trail had long gone cold: Friedrich Kadgien, a German official who had overseen the Nazi plundering of diamonds and gold across Europe. That discovery would ultimately lead investigators to a quiet seaside neighborhood in Mar del Plata, Argentina — and to a painting stolen from a Jewish art dealer during the Holocaust, “Portrait of a Lady.”

The case, which Argentine prosecutors now describe as one of the most significant Nazi-looted art recoveries in years, has thrown fresh light on the global tangle of stolen property, personal histories, and unresolved wartime crimes that continue to haunt Europe and South America alike.

In 2010, Post’s family was cleaning out his mother’s home in Driehuis, a small town west of Amsterdam, when they uncovered three handwritten diaries belonging to his father, Wim Post, who had died in 1976. The elder Post, a diamond specialist, had documented his experiences in 1942, when the Nazi occupiers ordered all Dutch diamond traders to surrender their stones — a raid that stripped Amsterdam’s Jewish and non-Jewish merchants of some 71,000 carats of precious gems, according to Reuters.

As The Algemeiner report noted, Wim’s detailed accounts of Nazi control over the Amsterdam Diamond Exchange gave his son a vivid sense of how the industry had been systematically gutted. Upon retiring from Hewlett-Packard, Paul began visiting the Dutch National Archives, where he soon encountered a recurring name in wartime records — Kadgien, the German official who had orchestrated the diamond seizures and subsequently vanished after Germany’s surrender.

Post’s curiosity grew into an obsession. “I’m not a historian, not an expert — just an amateur,” he told Reuters. “But I knew I was right on Kadgien.”

The trail led from the Netherlands to Switzerland, where Kadgien reportedly fled in early May 1945, just before Germany’s defeat. As historian Regula Bochsler in Zurich told Reuters, Swiss officials received intelligence that the fugitive Nazi had transferred large quantities of diamonds through clandestine channels. Yet by 1950, Kadgien had resurfaced with a visa to Brazil and eventually settled in Buenos Aires.

Post, working in collaboration with the Dutch newspaper Algemeen Dagblad, published his findings in 2015, in a series of reports by investigative journalist Cyril Rosman. The articles prompted renewed scrutiny of Nazi financial activity in Latin America — particularly Argentina, long known as both a refuge for Holocaust survivors and a haven for fleeing Nazis such as Adolf Eichmann and Josef Mengele.

By 2020, Post’s research intersected with another mystery: a database entry from the Cultural Heritage Agency of the Netherlands linking Kadgien to two missing artworks, including “Portrait of a Lady” by the 18th-century Italian painter Giuseppe Ghislandi (or, possibly, his contemporary Giacomo Ceruti), and a floral still life by Abraham Mignon.

Post’s inquiries led him to believe that Kadgien’s descendants might still possess these paintings. But when he met with the agency’s researcher, Perry Schrier, the official demurred. “He said, ‘It could be possible,’” Post recalled, “‘but how can we know it is on their walls?’”

That answer came years later, through the collaboration of Post, Rosman, and Peter Schouten, a freelance reporter based in Argentina. Acting on a hunch, they located Kadgien’s daughter, Patricia, now 60, who lived in Mar del Plata, a seaside town about 250 miles south of Buenos Aires.

In August 2024, as Reuters reported, the journalists discovered that Patricia’s home was listed for sale. When they examined the real estate photos, they noticed a painting hanging above her living-room couch — a poised woman in an 18th-century gown, unmistakably the long-lost “Portrait of a Lady.”

“I thought, is it really this simple?” Rosman told The Algemeiner. “A picture missing for eighty years just hanging there?”

Within days of the story’s publication, Argentine authorities raided the property — but by then, the painting had vanished, replaced by a tapestry of horses. Eight days later, Patricia’s lawyer, Carlos Murias, surrendered the artwork to the police.

Murias told Reuters that his client “had no knowledge” that the painting was looted and denied any wrongdoing. Yet federal prosecutors have since charged Patricia and her husband, Juan Carlos Cortegoso, with aggravated concealment and are investigating additional art pieces — over twenty drawings, prints, and two portraits — seized from both her home and that of her sister.

Prosecutor Carlos Martinez told Reuters that the couple’s actions spoke for themselves: “The attitude was to hide the painting. We think that isn’t indicative of someone who doesn’t know what they have.”

The painting’s provenance traces back to one of the most tragic and complex restitution cases of the Holocaust: that of Jacques Goudstikker, a Dutch-Jewish art dealer whose collection of over 1,000 works was seized by the Nazis after his death in 1940.

As The Algemeiner report detailed, Goudstikker perished while fleeing the German invasion, falling into the hold of a ship bound for England. In a small black notebook recovered from his belongings, he meticulously recorded his inventory — including “Portrait of a Lady.”

Soon after, Hermann Göring, the Nazi Reichsmarschall and Hitler’s chief art plunderer, orchestrated what historians now call a “forced sale” of Goudstikker’s collection. Göring’s associate, Alois Miedl, sold the portrait to none other than Friedrich Kadgien in 1944, according to the Reuters report.

Goudstikker’s heirs, led by his granddaughter Charlene von Saher, have spent decades battling for restitution. In 2006, the Dutch government returned more than 200 paintings to the family, many of which had hung for decades in public museums. Yet hundreds more remain missing.

When the discovery in Argentina became public, von Saher expressed a mix of astonishment and relief. “It’s like a movie,” she told Reuters. “I just hope that they would be people who would feel like doing the right thing and correcting a historical injustice.”

Patricia Kadgien, however, has maintained that the painting was acquired legally. In court filings cited by Reuters, she claimed that her father’s sister-in-law had purchased “Portrait of a Lady” in 1943 from the Wallraf-Richartz Museum in Cologne — an institution that has since denied ever possessing the work.

Her attorney insists the painting was “legitimately possessed” by her father and passed down through inheritance. Kadgien further argued that she removed the painting from her home “for security reasons,” believing she was the target of “a virtual scam” after receiving phone calls from a Dutch journalist.

Argentine prosecutors, however, are unconvinced. They point to the timing of the painting’s removal and the substitution of a tapestry as evidence of deliberate concealment. “The moment the story appeared, the painting disappeared,” Martinez told The Algemeiner. “That doesn’t look like an innocent act.”

Meanwhile, the Simon Wiesenthal Center has urged Argentina to expand its probe into Nazi-era assets, citing the country’s history as a refuge for fugitive war criminals. As Reuters reported, President Javier Milei met earlier this year with Wiesenthal representatives, who requested access to historical banking archives. In May, Argentina’s Supreme Court revealed the discovery of thousands of Nazi labor-organization membership booklets in its own archives — a stark reminder of how deeply embedded Nazi networks once were in the country’s postwar fabric.

Even as prosecutors unravel the art theft, Paul Post remains haunted by the other half of Kadgien’s legacy: the diamonds.

For years, Post has pursued leads suggesting that Kadgien may have smuggled part of the looted Dutch diamond cache into South America. But when Argentine police searched the Kadgien home, they found no evidence of jewels or war-era valuables, according to the Reuters report.

Historians caution that definitive proof may never emerge. “It’s very hard to trace whether Nazis took diamonds with them to South America,” said Saskia Coenen Snyder, a Dutch-born historian of Jewish history at the University of South Carolina, speaking to Reuters. “But I’ll give him credit — he’s a bit of a pit bull. He’s spent years chasing stories that few others have had the tenacity or courage to follow.”

As The Algemeiner report observed, the Post-Kadgien case encapsulates the broader challenges of post-Holocaust restitution: the entanglement of private memory, bureaucratic inertia, and moral accountability across generations.

Nearly 600,000 artworks were looted by the Nazis between 1933 and 1945. Of those, more than 100,000 remain missing, scattered through private collections, museums, and estates across Europe and Latin America. Each recovery — whether of a priceless Vermeer or a modest portrait — reopens questions about complicity, restitution, and historical justice.

“Portrait of a Lady,” valued at roughly $100,000, is modest in monetary terms compared to some masterpieces recovered in recent years. But its symbolic weight is immense. “Every object like this represents an individual life, a stolen dignity,” one restitution lawyer told The Algemeiner. “Returning them is not about art — it’s about repairing history.”

For Paul Post, what began as a personal act of curiosity has become a mission that links family duty with global justice. His father’s wartime diaries, meant as a private record of survival, have evolved into a catalyst for international accountability.

“Sometimes history hides in plain sight,” Post said in a recent Reuters interview. “You think it’s all gone — and then you find it hanging in someone’s living room.”

Indeed, the image of the painting—hung casually above a sofa in an Argentine home, its violent provenance obscured for decades—has become an emblem of how the remnants of atrocity persist in the most ordinary of spaces.

The Algemeiner, reflecting on the case, called it “a story of moral archaeology,” one in which “an attic in Amsterdam exposed a secret buried for eighty years in South America.”

As of this writing, Argentine authorities continue to hold the recovered painting under judicial custody. Prosecutor Martinez told Reuters that his office will collaborate with international agencies to authenticate its provenance and coordinate its return. The Dutch government and the Goudstikker heirs are preparing formal restitution claims, while Kadgien’s defense attorneys are expected to appeal the charges of concealment.

Whatever the court’s eventual ruling, the case underscores a profound truth that both Reuters and The Algemeiner have emphasized throughout their coverage: history resists silence.

For decades, “Portrait of a Lady” hung quietly, her gaze fixed on no one in particular. Now, as investigators, journalists, and descendants piece together her journey from Nazi Europe to South America, she has become something more — a witness to endurance, a reminder of how injustice, no matter how artfully framed, can never be permanently hidden.

And for Paul Post, whose father once chronicled the brutal efficiency of Nazi theft, the discovery feels like a full-circle moment. “I never thought it would lead here,” he told Reuters. “But maybe this is what my father wanted — for someone to keep asking questions.”

As both Reuters and The Algemeiner continue to follow the unfolding legal proceedings, one thing is certain: the ghost of Friedrich Kadgien’s crimes has finally been dragged into the light, not by institutions or governments, but by a retired engineer armed only with his father’s words — and the conviction that the truth, no matter how deeply buried, is always worth finding.