In a hidden treasure room dedicated to celebrating the Third Reich, Argentine police officers have found a trove of Nazi artifacts, including a bust of Hitler, that they believe were brought to the country by fugitive Germans.

The police said on Tuesday that they had uncovered the collection of more than 75 artifacts outside Buenos Aires, in the suburban home of a collector whom they have not yet named.

“After investigating,” said Marcelo El Haibe, the federal police commissioner for the protection of cultural heritage, “we were able to discover those objects that were hidden behind a bookcase. Behind the bookcase there was a wall, and after that a door.”

Inside the secret chamber, the police found what they said were authentic Nazi artifacts that probably belonged to high-ranking party members during World War II.

Among the items, the police said, were a magnifying glass and photo negatives that appeared to show Hitler holding the same lens. “We have turned to historians, and they’ve told us it is the original magnifying glass” used by Hitler in the photograph, said Nestor Roncaglia, the head of Argentina’s federal police.

The police also found toys and musical instruments, including a box of harmonicas, emblazoned with swastikas and Nazi symbols, that would have been used to indoctrinate children.

“There are Nazi objects used by kids, but with the party’s propaganda,” Commissioner El Haibe said. He added, “There were jigsaw puzzles and little wood pieces to build houses, but they always featured party-related images and symbols.”

The authorities said they had uncovered the collection in the course of a wider investigation into artwork of suspicious origin found at a gallery in Buenos Aires.

Agents of Argentina’s federal police and Interpol, the international police force, raided the collector’s house on June 8. The collector was not at the house at the time, and has not been charged, but is under investigation, the police said.

The authorities also found medical devices associated with the Nazis’ eugenics programs, including a tool used to measure people’s heads as a way of assessing their supposed racial purity.

“We know the history, we know of the horrible experiments conducted by Josef Mengele,” said Ariel Cohen Sabban, president of the Delegation of Israelite-Argentines Associations, the country’s largest Jewish organization.

Mengele, a notorious Nazi physician, fled to Argentina to avoid prosecution for war crimes in Europe. He lived in the capital for a decade and eventually died in Brazil in 1979.

“When I see these objects,” Mr. Sabban said, “I see the infamy of that terrible era of humanity that has caused so much damage, so much sadness.”