During World War II, Mengele served at the Auschwitz extermination camp in Nazi-occupied Poland, where about 1.1 million people were killed, around 1 million of them Jews.
He became infamous for carrying out brutal medical experiments on inmates, including children, under the guise of scientific research.
After the war, Mengele obtained a Red Cross travel document under a false identity, allowing him to leave Europe. Like many former Nazi officials, he spent years in hiding in Latin America while being pursued internationally for his crimes. He drowned in 1979 while swimming on the coast of Brazil.
The documents released by Swiss authorities include material provided to police suggesting that Mengele may have returned to Switzerland after initially fleeing Germany, or may have been planning to enter the country under a false name, according to the German news agency dpa.
