After World War II, many high-ranking Nazis escaped to Argentina. There, they concealed their identities and tended to live out of the public eye. Now a massive cache of original Nazi artifacts—including a photograph of Adolf Hitler and a ghoulish cranial-measurement device—has turned up in a secret room in a suburb outside of Buenos Aires, the capital. It appears to be the largest discovery of original Nazi artifacts in Argentina’s history.

On June 8, Argentine police, in conjunction with international police force Interpol, raided the home of an undisclosed collector in the suburb of Béccar. There, behind a bookshelf leading to a secret passageway, they discovered a hidden room containing approximately 75 Nazi artifacts, including a magnifying glass that is believed to have been used by Adolf Hitler himself. All of the pieces found are authentic Nazi relics.

Several magnifying glasses engraved with swastikas were found next to a photo negative of the Nazi leader using what looks to be the same magnifying glass, Argentina’s federal police chief Nestor Roncaglia told the Associated Press. Other pieces found among the collection include a medical device used by Nazi doctors to measure head size, a factor used by Nazis in determining a person’s racial purity, and a large bust of Hitler.

Investigators have not come to a conclusion about the origin of these artifacts, and experts on Nazi loot are divided about how, exactly, these items may have made their way to Argentina. As World War II came to a close, some Nazis fled to other countries using “ratlines,” underground networks for fugitive Nazis. Wanted Nazi war criminals fled to several countries in South America, including Argentina, to avoid answering for their crimes in Germany.

High-ranking officials like Josef Mengele, a concentration camp physician known as the “Angel of Death,” and top camp administrator Adolf Eichmann settled in Argentina. In 1960, Eichmann was kidnapped by Israeli agents from his home in Buenos Aires and brought to Israel to stand trial; he was later executed.

Argentina kept a sympathetic, pro-Nazi stance for some time under the rule of President Juan Domingo Perón, and it’s possible the artifacts found in Argentina were brought by Nazis themselves, said Dr. Wesley Fisher, Director of Research for the Conference on Jewish Material Claims Against Germany. “They clearly were bringing with them paraphernalia that was important to the Nazi regime.”

Fisher said items such as these would have originally belonged to senior officials in the Nazi government, but could have been stolen from them and dispersed by other persons later. “There may be an underground or secret market for these things,” said Fisher. “But it would seem more likely that these items were brought in after the war.”

Not all experts agree. Guy Walters, author of the 2009 book Hunting Evil: The Nazi War Criminals Who Escaped and the Dramatic Hunt to Bring Them to Justice, said there’s no way that the artifacts found in Argentina would have come from high-ranking Nazis. “Adolf Eichmann and Josef Mengele escaped with very little luggage,” said Walters. “[Eichmann] was not the type of man to collect artifacts. Mengele was a richer man, but again, it makes no sense for someone like Josef Mengele to collect that amount of Nazi junk.”

The Nazis who escaped via the ratlines were only able to carry “a couple of suitcases” with them, noted Walters, and would not have had enough room for the sheer number of artifacts that were found in Argentina. Plus, most S.S. officers worked hard to conceal their identities after fleeing Germany. “The idea that they were traveling with objects like Hitler’s magnifying glass is simply unbelievable,” he says. “This is only a secret collection because it’s tasteless.”

As for the significance of the medical equipment and the photo negative of Hitler using the magnifying glass? There are lots of objects that Hitler touched, but it doesn’t mean they would belong to a senior Nazi, Walters said. “There are a lot of people in the world who collect Nazi memorabilia, and some of them live in Argentina,” said Walters. “They’re not illegal. You can buy this stuff on eBay.”

Since being discovered, the artifacts have been put on display at the Delegation of Argentine Israelites Associations, in Buenos Aires.