Nazi doctor Josef Mengele was infamous for the horrific experiments he performed on concentration camp prisoners during the Holocaust. Now an Argentinean researcher reports that after fleeing to South America Mengele continued his experiments, and succeeded in creating a “twin city” with an unusually high number of blond children.

Researcher Jorge Camarasa says Mengele was responsible for the many twin births in the small town of Candido Godoi in Brazil. Mengele visited the town while living in nearby Paraguay, and over the years began treating local women, Camarasa says in his book Mengele: the Angel of Death in South America.

Mengele used Cadido Godoi as a laboratory, Camarasa told the British Telegraph this week. After Mengele began treating women in the 1960s, local women began experiencing an unusually high number of twin births.

While the normal ratio of twin births to single-child births is roughly one to 80, in Candido Godoi the ratio shot up to one in every five births, confounding scientists. Most of the twins were blond with blue eyes—features considered highly desirable under the Aryan supremacist views held by Mengele and his fellow Nazis.

During the Holocaust, much of Mengele's research centered on attempts to assure the birth of twins, in order to increase the Aryan birthrate. He also attempted to single out typically Aryan physical characteristics and discover how to replicate them.

As the twin births continued, local doctors began interviewing women, and discovered that all described the same man: a doctor going by the name of Rudolph Weiss. The doctor would visit the town and go from door to door, giving women various syrups and pills that he said would heal them, women said. He also performed dental work and frequently took blood samples.

According to Camarasa, in Brazil Mengele “finally managed to fulfill his dreams of creating a master race of blond-haired, blue-eyed Aryans.” Mengele managed to continue his life without being brought to justice until his death in 1979.