March 16, 1911 - February 7, 1979: Age 67
Mengele was the notorious physician at the Nazi concentration camp Auschwitz-Birkenau. He was among the physicians who supervised the selection of prisoners arriving, deciding who would die quickly, who would be a slave, and who would be selected for human experiments. He was known as the "Angel of Death" ("Mengele" contains "Engel", the german word for "angel". He used his work at Auschwitz to continue his research on heredity, and had a special interest in twins, trying to prove that various diseases were caused by racial inferiority. Those selected for "special work detail" with Mengele were better housed and fed than the others, and temporarily safe from the gas chambers, but most of his victims died due to the experiments he performed or of later infections. According to his assistant/slave, a prisoner with a medical degree and was an experienced pathologist, Mengele simply did not consider his subjects to be fellow human beings.
At the end of the war he was captured by Americans, but gave his name as "Fritz Hollman" and worked as a farmhand. Eventually a friend helped him escape to Argentina, where he worked as a construction worker. Soon he came into contact with influential German expatriates there and began to enjoy a good life. By 1960, however, fear of capture drove him to Paraguay just a few weeks before the Israeli Mossad captured Adolf Eichmann in Argentina and took him to Jerusalem for trial as a war criminal. They had intended to capture Mengele as well, but he had already fled. Run by a dictator of German heritage (Alfredo Stroessner), Paraguay was safer.
He was already infected, however, with a sense of anxiety, and this anxiety haunted him for the rest of his life. He crossed into Brazil and went into hiding under an assumed name, living with a Neo-Nazi admirer there. He moved out into the country and worked as a manager of a farm. His mental state deteriorated; he became depressed, angry, and self-centred. Always fearing capture, he rejected a proposal to relocate in Bolivia in 1974 and moved instead to a bungalow in a suburb of São Paolo, where his son Rolf visited him in 1977. According to his son (who was anti-Nazi and had never known his father), Mengele was unrepentant, claiming he "had never personally harmed anyone in his whole life."
His health deteriorated, Mengele died two years later while swimming in the sea. He either drowned accidentally or as a result of a stroke. He was buried under the name "Wolfgang Gerhard", the identity he had used since 1976.
He did manage to elude his enemies, at least the external ones. In 1985 police found evidence of his hiding place and death at the house of one of his friends in Germany. His body was exhumed in 1985 and positively identified by forensic experts. Later, in 1992, a DNA test confirmed the identification beyond a doubt.
Sources: Wikipedia, Mengele: The Complete Story