Name of Nazi executioner in horrific WWII photo revealed using AI after 80 years of searching

Often associated with scams and deepfakery, AI is now being used for another, more noble purpose: unmasking history’s monsters.

A German historian has utilized the omnipresent tech to glean the identity of a notorious Nazi executioner in a World War II photograph — over 80 years after it was taken.

“The match, from everything I hear from the technical experts, is unusually high in terms of the percentage the algorithm throws out there,” German historian Jürgen Matthäus, the sleuth who solved the mystery, told the Guardian.

In the chilling photo, taken in today’s Ukraine, a bespectacled Nazi soldier aims a pistol at a man who’s kneeling before a mass grave as other SS troops look on.

Commonly known as the “Last Jew of Vinnitsa,” the pic remained a mystery for decades until Matthäus cracked the caper with the aid of AI, historical records and personal accounts.

According to the study published in the Journal of Historical Studies, the massacre took place July 28, 1941 in the citadel of Berdychiv and not Vinnitsa as previously thought. The regiment, Einsatzgruppe C, had reportedly been charged with eradication of “Jews and partisans” in the newly occupied Soviet region ahead of a visit by Adolf Hitler.

The gunman is believed to be Jakobus Onnen, a French, English and gym teacher who was born in 1906 in Tichelwarf, Germany, and joined the Nazi party in 1931.

Matthäus happened upon this revelation in part due to a stroke of luck, when, after word of the massacre’s real whereabouts, date and unit circulated in German media last year, a reader came forward with some vital information.

Based on correspondence from the time in his family’s possession, he said that the shooter bore a striking resemblance to his wife’s uncle, Onnen, and provided the aforementioned biographical details.

The pics were then sent to open-source journalism group Bellingcat volunteers, who were able to forensically analyze it using AI.

When coupled with the strong likeness and strong circumstantial evidence, it seemed like a perfect enough match to publish, per Matthäus.

While AI was undoubtedly integral in this historic eureka moment, Matthäus maintained that the tech is “not the silver bullet” but “one tool among many” and that “the human factor remains key.”

It’s not clear what prompted Onnen to radicalize, but he was reportedly a dedicated Nazi. In August 1939, just before the outbreak of war, he enlisted in the SS Death’s Head Unit at Dachau concentration camp and was working for the Nazi “Order Police” in occupied Poland by 1940, the Independent reported.

He then joined the Einsatzgruppe C — with whom he’d be snapped carrying out his horrific execution — in 1941, shortly after the Nazi invasion of the Soviet Union. The unit reportedly eliminated all but 15 of the 20,000 Jews that were there upon their arrival.

“These mass executions in this format continued until the very last day of the German occupation in the east,” Matthäus said. “I think this image should be just as important as the image of the gate in Auschwitz, because it shows us the hands-on nature, the direct confrontation between killer and person to be killed.”

Despite his fervor, Onnen reportedly was never promoted beyond a low rank and was killed fighting partisans in the Zhytomyr region of Ukraine in 1943.

Unfortunately, his kneeling victim has yet to be identified, but Matthäus said he plans to remedy that as part of his next project using Soviet-era records and, possibly, the aid of AI.