The break came in the form of a tip, not to law enforcement but to a journalist. “I can’t tell you on the phone, but I need to see you in person,” said the caller. “It’s important.”

For several years he had been a reliable source for me. “I am flying via Frankfurt tomorrow and will have some time around noon,” he told her. “They agreed on a place near the city’s famous Hauptwache plaza.

The source produced a file with a photograph of a middle-aged man in a suit and tie. In the lower left-hand corner, part of a stamp with markings in Arabic was visible. “Do you know who this man is?” he asked. She said she did not. “Aribert Heim. They also call him Dr Death.”

After extracting a promise of anonymity, the tipster revealed where the Nazi fugitive had fled when he left Germany in 1963.

[Excerpted from “The Eternal Nazi” By Nicholas Kulish and Souad Mekhennet]

This was in 2008, the beginning of more than five years of investigative reporting and writing for my colleague, Nicholas Kulish and me. The work on the resulting book was challenging and sometimes even life threatening: in Egypt in 2011, we ended up in jail together along with our driver, when we were stopped at a checkpoint on the way to Cairo. Police found camera equipment and a microphone from a German TV crew in our car and turned us over to the secret police for interrogation. We could hear screams and the sounds of prisoners being beaten while held in prison for 24 hours.

We continued with our work, despite the ongoing threat of getting arrested again. We were on the trail of Dr Aribert Heim, one of the most hunted Nazi war criminals identified by the Simon Wiesenthal Centre. He was accused of performing operations on prisoners without anesthesia; removing organs from healthy inmates, then leaving them to die on the operating table; injecting poison, including gasoline, into the hearts of others; and taking the skull of at least one victim as a souvenir.

For decades, Nazi hunters, intelligence services and law enforcement agencies had looked for him all over the world. But he had successfully covered his tracks until we eventually traced the story of how he had hid in Egypt, assuming the name of Tarek Hussein Farid and converting to Islam, before his death in 1992.

We broke the story in the New York Times and in a documentary for German TV, before publishing the book.

The publicity has led a lot of people to ask me if it felt “weird” or “strange” hunting for a “most wanted Nazi” given my own background.

Born in Germany, I am the daughter of a Turkish mother and Moroccan father, an Arab. “How do you think the Arabs will react?” asked some. “How do you think Germans will react?” asked others.

Indeed, I have been thinking about it a lot myself. This reporting has also been a journey into my own past and family history.

My father’s parents are from Meknes, Morocco, where I lived briefly as a child. They used to tell me: “Beware of those who preach the differences between people and try to destroy what humans have in common.” My grandfather was the first victim of torture that I met. The second was my maternal grandfather in Turkey.

My two grandfathers never met in person because they were too sick and weak to travel. But what they had in common they shared with thousands of others. They had been victims of colonizers; their torturers came from Spain and France. There has never been an apology from either country, nor has my Moroccan grandfather ever gotten his seized land back. Even so, what both of my grandparents also shared was their openness towards people of other religions and cultures, and my siblings and I were instilled with this sense of respect towards others.

My Moroccan grandmother always invited neighbours over for Moroccan teatime. Our closest neighbours thus became family, and so did their little girl, who was my best friend. Her name was Sara, and she was Jewish. We ate the same food and played together. We were apart only when I went to my Imam to learn about Islam, and she joined children in her community to study Judaism.

“Don’t judge a person by what their religion is or if they are poor or rich, judge them by how they behave and treat others,” my grandmother used to say. This sentence became a credo for my whole life.

I was almost five when Sara left with her family for France, and my parents brought me back to Germany. I went to kindergarten in our Protestant community, and acted the part of the Virgin Mary twice during the Christmas play. One day after school, I asked my mother why there weren’t any Jewish children there, like my friend Sara?

She tried to explain to me that something “very bad” had happened in Germany and that Jews and other people, including the handicapped, like my oldest sister, had not been treated well. “Therefore the Jewish children go to a Jewish kindergarten and school.”

I often visited our neighbours, an elderly couple called Mr and Mrs Weiss, who were Holocaust survivors. They would tell me, “A democracy can also turn into something evil, see what has happened to us here in Germany.” Once I asked how they could bear to live there given what happened, and Mr Weiss answered, “I don’t want them to forget, but I also don’t want the Nazis to win, because they wanted us to leave and I will not.”

In the early 1990s, after German reunification, we witnessed many attacks from Right Wing extremists and Neo-Nazi groups against migrant families. People were killed and injured in November 1992 in the city of Mölln and in 1993 in Solingen. Once my brother and I were followed by a group of Skinheads in a car, who screamed, “Gypsies, we will get you and gas you.”

I went back home and begged my parents to leave Germany. “They hate us here, they will burn us, like they did with the Jews.” My parents told me not to forget there were good people and bad people in this world, but that we should trust that there were more good than bad people in Germany. After calming down I eventually remembered the words of my Jewish neighbour. “Don’t let them win, these extremists,” I said to myself.

I stayed in Germany. I would be lying if I didn’t say there have been moments when I felt discriminated against because of my name or my heritage. Some of my American colleagues asked me if I would ever be fully accepted by most people as a German. I am still struggling to find clear answers to that question.

At the same time I found it intriguing to see Jews as advisers and members of upper houses in Arab countries like Morocco and Bahrain, and I think sometimes that some Western countries could learn something from other cultures too.

Seeing now how extremist right-wing groups and parties have risen in Europe in recent months, I often remember the words of Alfred Weiss about how the Nazis came into power. I remember my grandparents’ stories about how Western countries colonialized them and never apologized for any wrongdoing.

Back then, neither they nor I would have thought that one day the German Muslim daughter of immigrants would help solve the case the most hunted Nazi war criminal in the world.

“The Eternal Nazi” does tell his story. But it also tells the stories of those who were searching for him and the truth – Germans, Israelis, Americans and Arabs; Christians, Jews and Muslims.

Author: Souad Mekhennet is a journalist, author and World Economic Forum Young Global Leader.

Image: A woman walks through the Holocaust memorial in Berlin, November 26, 2010. REUTERS/Pawel Kopczynski