A new analysis of Adolf Hitler's teeth and bones puts to rest questions of how he died.

In a new study, French scientists analyzed fragments of Adolf Hitler’s teeth to prove that he died in 1945, after taking cyanide and shooting himself in the head. The research, published in the European Journal of Internal Medicine in May 2018, seeks to end conspiracy theories about Adolf Hitler’s death through scientific analysis of the dictator’s teeth and skull.

“Our study proves that Hitler died in 1945,” lead study author Philippe Charlier told AFP. “The teeth are authentic, there is no possible doubt.”

Though it’s widely established that Hitler died in his bunker in Berlin, rumors of his escape abound. Their research proves that “he did not flee to Argentina in a submarine, he is not in a hidden base in Antarctica or on the dark side of the moon,” said Charlier.

In late April 1945, as Soviet forces stormed Berlin, Hitler made plans for his suicide, including testing SS-supplied cyanide pills on his Alsatian, Blondi, and dictating a final will and testament. Two days earlier, Mussolini had been shot by a firing squad and then publicly hung by his feet in a suburban square in Milan, Italy: A similar fate seemed inevitable.

Late on April 30, the bodies of Hitler and his new wife, Eva Braun, were found in the bunker, with a bullet hole in Hitler’s temple.

Adolf Hitler on a German WWII poster, 1943. Galerie Bilderwelt/Getty Images

In April 2018, the English publication of the memoirs of a Russian interpreter revealed how she had been entrusted with a set of teeth in 1945, and tasked with cross-checking them against the dictator’s dental records: They matched, and have remained in Russian hands ever since, the Telegraph reported.

After months of negotiations, Russia’s FSB secret service and the Russian state archives gave the researchers permission to examine a skull fragment and bits of his teeth. The piece of skull had a hole on its left side, consistent with a bullet wound, with black charring around the edges. Though scientists weren’t allowed to take samples from the skull, they noted in the study, its shape seemed “totally comparable” to radiographies of Hitler’s skull taken a year before his death.

Gruesome pictures of the teeth published in the study show a jaw made mostly of metal. “At the moment of his death,” they wrote in the report, “Hitler had only four remaining teeth.” The few there are misshapen, brown at the base, and flecked with white tartar deposits.

The analysis corroborated frequently-cited claims that Hitler was a vegetarian, but could not conclusively prove whether he took cyanide before the gunshot. Bluish deposits on his false teeth, the researchers wrote, suggest a variety of different hypotheses—did some chemical reaction take place between his fake teeth and the cyanide at the moment of death, during his cremation, or while the remains were buried?

Without taking samples for analysis, it’s hard to say for sure. “We didn’t know if he had used an ampule of cyanide to kill himself or whether it was a bullet in the head. It’s in all probability both,” Charlier said.

Either way, the study may help finally put to tales of Hitler’s flight to rest, once and for all.