In July 1949, a 48-year-old man died of unknown causes in a Vatican hospital in Rome. A few months earlier, he had assumed a false identity, that of Alfredo Reinhardt.
The last months of his life had been spent in a monastery in a southern suburb of Rome.
But the story of who he really was and how he ended up there is one that leads to the very heart of Nazi Europe and the slaughter of roughly 11 million people, including six million Jews.
As law professor and barrister, Philippe Sands reveals in his new book, The Ratline, the man's real name was Otto Wächter
An Austrian Nazi, he had held the position of governor of Krakow, in Poland, and then of Galicia, the region straddling the modern-day border of Poland and Ukraine. Between 1939 and 1945, hundreds of thousands of Jews from the regions under his control were sent to their deaths.
World War II ended in Europe 75 years ago, but in the aftermath of what philosopher Hannah Arendt described as "the darkest and deepest abyss", the vast majority of senior and mid-level Nazi officials escaped justice.
Otto Wächter was one of them. He spent four years on the run, receiving help every step of the way.
The ratline was the term used for the escape routes devised by Nazi sympathisers for those fleeing capture.
In his book, Sands follows a trail that begins in Austria, passes through the Alps, Germany, Poland and Ukraine, before concluding in Italy. It is one that implicates the Vatican, the United States Counterintelligence Corps and others.
During his research, he excavated archives, ate cake with the sons of Nazis and climbed the Alps. He did so, in part, because the story of Otto intersects with that of his own family.
For Sands, it all began in 2010 when he was invited to deliver a lecture on crimes against humanity in Lviv, a city in Ukraine.
While there, he found the house in which his maternal grandfather, Leon Buchholtz, had been born. In 1904, the year of Buchholtz's birth, the city was called Lemberg, and it was a regional capital of the Austro-Hungarian Empire.
Sands hoped to fill in gaps in his understanding of his grandfather's identity and, by extension, his own. Although Sands's grandfather survived the war, almost every other member of his family was killed.
He began to research the life of Hans Frank, the governor-general of German-occupied Poland between 1939 and 1945; the man under whose governorship Buchholtz's family was exterminated.
Frank was convicted of war crimes and crimes against humanity and hanged at Nuremberg.
In the course of his research, Sands arranged to meet Frank's son, Niklas. In time, the two men became friends.
According to Sands, Niklas "despised his father", having once declared: "I am against the death penalty, except in the case of my father."
But he introduced Sands to another son of a Nazi who did not feel the same way - Otto's son, Horst Wächter.
In the spring of 2012, Sands visited Horst in his dilapidated 12th-century baroque castle, Schloss Hagenberg, near Austria's northern border. Eventually, after years of correspondence, Horst decided to share his family's vast archive with Sands.
In it were more than 800 letters between Horst's mother, Charlotte, and his father, Otto, written between 1929 and 1949, as well as Charlotte's diaries and accounts of their life together that she wrote 40 years later.
Together, they paint a picture of a couple close to the most senior members of the Nazi party, among them Adolf Hitler and Heinrich Himmler; of a man responsible for the deaths of hundreds of thousands of men, women and children and a woman who embraced Nazi ideology just as fervently; of a family who enjoyed art, opera and nature in the midst of the Holocaust; and of a desperate bid to evade capture and justice as the second world war came to an end.
The story began in 1929 when 20-year-old Charlotte Bleckmann, the daughter of a wealthy Austrian steel mill owner, accepted an invitation to spend a weekend skiing with a friend.
On the train to Schneeberg, she met a 27-year-old Austrian lawyer.
The young lawyer was Otto . The son of an officer in the imperial Austro-Hungarian Army, he had studied law at the University of Vienna, where he became politically active.
An early supporter of Hitler, he had taken part in a large anti-Jewish protest organised by an organisation called the Antisemitenbund in central Vienna in 1921. He had been arrested and tried and spent 14 days in prison. On April 1, 1923, he had become a member of the Nazi party.
During their courtship, Charlotte and Otto took long walks in the park and went boating.
In March 1931, Charlotte gave Otto a copy of Hitler's Mein Kampf.
In May of that year, she became a member of the Nazi party. Soon, Otto became district chief of the Nazi party in Vienna. Then, in April 1932, he joined the SS.
But Charlotte's diary rarely made reference to his political activities.
They married on September 11, 1932. Charlotte was pregnant at the time.
On March 5, 1933, the Nazis won the German federal elections. A little over two weeks later, Hitler gave himself absolute power.
Charlotte and Otto's first child, Otto junior, was born a few days later, on April 2. They would have six in total.
The following year, on July 25, 1934, Austrian Nazis attempted to overthrow the government of Engelbert Dollfuss, himself a fascist but one more closely aligned with Italy's Benito Mussolini than Hitler. He opposed the annexation (or Anschluss) of Austria that Hitler so desired and had banned the Nazi party in Austria.
The attempted coup failed, but Dollfuss was killed.
Thirteen Nazis were arrested, tried and hanged in the streets of Vienna.
Otto's exact involvement in the plot was never clear. But he was indicted by the Austrian state for high treason. He fled Vienna before he could be arrested.
After several days with no news of him, Charlotte learned that Otto had found refuge in Berlin.
In Germany, Otto completed his military service, qualified to practice law there and rose quickly through the ranks of the SS.
Back in Austria, Charlotte returned to her hometown of Mürrzzuschlag with their baby son, where she received visitors and played chess.
In September 1935, the Nuremberg Laws were passed by the German Parliament, the Reichstag. They stripped Jews of German citizenship and banned marriage between Jews and non-Jewish Germans, providing the legal framework for the systematic persecution of Jews in Germany.
In the autumn of 1936, after two years apart, Charlotte drove from Austria to Germany, collecting Otto from the barracks at Freising where he was completing his military service at the Dachau concentration camp, before driving him to Berlin. Dachau, the first concentration camp created by the Nazis, was initially a camp for political prisoners.
In Berlin, Otto was offered a job in the SD, the intelligence agency of the SS.
When, in early 1937, he was promoted to SS-Obersturmbannführer, his personnel file described him as having an "upright and open" character, of being well-educated, with common sense, and perfect "racial characteristics", namely "tall, slender, with Nordic appearance".
But things were not progressing so well in Charlotte and Otto's marriage. Charlotte learned that Otto had had an affair. It was not his first. Charlotte was pregnant at the time and responded by terminating the pregnancy.
In January 1938, Heinrich Himmler, the leader of the SS, promoted Otto to SS-Standartenführer.
But developments in Austria meant the Wächters would not stay in Berlin for long.
On March 11, 1938, Otto's friend Arthur Seyss-Inquart became governor of Austria. The following morning, German troops marched across the border. The annexation was complete.
Forty years later, Charlotte described how this "single event changed everything, and our wildest dreams, which we never imagined could be realised, suddenly came true."
Charlotte and Otto returned to Vienna in time to witness Hitler's arrival.
Otto and Charlotte had secured seats on the balcony of the Heldenplatz. For Charlotte, that time with Hitler was "the best moment of my life".
Shortly afterwards, Otto was offered a position as state commissioner.
Within a week of the Anschluss, a new constitutional provision allowed for the reform of public bodies. According to Section 3 of the ordinance restructuring the Austrian civil service, all Jews and part Jews (Mischlinge) would be automatically dismissed.
Otto set about his task of cleansing the Austrian civil service with ruthless vigour, even dismissing some former law professors at the University of Vienna. In time, he dismissed at least 16,237 civil servants, many of whom were transported to concentration camps.
On November 9, 1938 - Kristallnacht (the Night of Broken Glass) - Charlotte attended the premiere of a new play, Cromwell at the Burgtheater in Vienna. While she watched the play, on the streets of Vienna, Jewish homes, shops and synagogues were ransacked, burned and destroyed.
Twenty-seven Austrian Jews were murdered during the pogrom. About 6,000 were arrested and deported - almost all of them to Dachau.
But Charlotte made no mention of those events in her diary.
Charlotte's own private drama during this time revolved around her discovery that Otto had had another affair. Still, she immersed herself in Vienna's cultural delights, attending a concert of Mozart and Beethoven conducted by Furtwängler and a performance of Die Fledermaus by Johan Strauss. She spent New Year's Eve at Vienna's annual Opera Ball.
"Afterwards home and waited for midnight alone," she recorded.
On the morning of September 1, 1939, the Nazis invaded Poland.
Two days later, on September 3, Britain and France declared war on Germany.
On September 29, Germany and the Soviet Union divided Poland between them - the Germans taking everything west of the Bug River and the Soviets everything to the east of it.
On October 8, Hitler annexed large parts of western Poland.
A few days later, Hitler declared Hans Frank the governor-general of German-occupied Poland - those parts that had not been directly annexed. Frank set up his residence and headquarters at Wawel castle. Otto's close friend, Arthur Seyss-Inquart, was appointed as his deputy.
On October 17, 1939, Otto became chief administrator for the District of Krakow, one of the four new districts of Poland. But within a month, Seyss-Inquart was moved to another position and Otto was appointed governor of Krakow. Otto established his office in the Potocki Palace, on Krakow's main square.
Charlotte and the children - they now had four - remained in Vienna.
"Otto came home rarely," Charlotte noted, but he wrote often.
Charlotte rejoiced in her husband's new work, and the "humane and sympathetic" way he exercised power.
On his first day as governor on November 11, 1939, Otto signed an order with the title, Marking of Jews in the District of Krakow. It required Jews over the age of 12 to wear a blue Star of David on a white armband, precisely 10cm (four inches) wide. Those who failed to comply faced "severe punishment".
The order to shoot the men had come from Berlin. It was a reprisal for an attack on a police station, in which two German police officers had been killed. The two perpetrators, members of a Polish underground organisation called White Eagle, had been caught and hanged from street lamps.
On December 18, 1939, about 50 men from Bochnia, near Krakow were rounded up, led across a snow-covered field and shot, before being buried in a mass grave that local Jews had been forced to dig. According to witness accounts, Otto attended the mass execution.
A few months later, in the spring of 1940, Charlotte joined Hans Frank and his wife, Brigitte, on a trip to Vienna. They travelled on a "special train" - the night sleeper.
"My heart leapt for joy at being in my much-loved home city," wrote Charlotte.
She walked through the city with Frank.
Germany was winning more and more ground. "Holland capitulates," Charlotte wrote in her diary on May 15, 1940. Three days later, "Brussels falls". And on June 23, "France peace agreement signed yesterday" - a reference to France's surrender.
Heidegund, Charlotte and Otto's fifth child, was born on October 16, 1940, in Vienna. A "sweet, intelligent thing," she wrote.
Charlotte moved to Krakow shortly after but was unhappy with her new house there.
Otto planned to cheer her up by buying a vast castle on the River Vistula.
He immersed himself in his work, expelling tens of thousands of Krakow's Jewish inhabitants to the surrounding countryside.
During this time, Charlotte helped herself to "the most exquisite paintings and the most beautiful items of antique furniture," including Gothic and Renaissance chests, armour, bowls, furniture and paintings from the museum in Krakow, said the director of the Kunsthistorisches Museum in Krakow at the time, Professor Feliks Kopera.
She is said to have also taken Pieter Bruegel's famous The Fight Between Carnival and Lent, painted in 1559. Kopera accused her of having caused the museum "great harm" by taking such valuable works.
Some of them were returned after the war, others were not.
On March 3, 1941, Otto signed the decree to establish the Krakow ghetto in the Podgorze district. All Jews remaining in the city were required to move into it. They were allowed to take just 25kg of personal belongings with them. Over time, Jews from other communities were also forced into the ghetto. Eventually, about 20,000 Jews lived within its boundaries - in an area that had previously housed 3,000.
At around the same time, Charlotte complained to Otto: "It's my destiny to be unhappy." She sent instructions for the renovations of their new house: Otto should make her a fitted wardrobe and follow the plan she had sent him.
During this time, he attended cabinet meetings at Wawel Castle.
In November, Otto and Charlotte hosted a roofing ceremony for their new home, Schloss Wartenberg, which overlooked the Vistula River.
On January 20, 1942, the Wannsee Conference, a meeting of senior government officials, in Germany, settled the details of the "final solution to the Jewish question".
As a result of the meeting, a network of extermination camps was established.
On January 23, Otto was appointed governor of the District of Galicia, a part of southern Poland with Lemberg as its capital, today part of western Ukraine.
Charlotte learned that Otto had been personally selected by Hitler.
Otto arrived in Lemberg, modern-day Lviv, on January 28, 1942. Within a few weeks, he had signed a decree prohibiting Jews from certain employment. Within a year, most of the Jewish population of Lemberg - more than half a million people - had been "liquidated".
Otto spent two-and-a-half years in Lemberg, a time of "enormous joy", during which he implemented "his own ideas on humane and good governance", Charlotte wrote in her diary.
In the summer of 1942, they spent a few months apart. It was during this time that Charlotte fell in love with Hans Frank.
In August 1942, the Grosse Aktion began as Jews in Lemberg were rounded up. Some were shot. The Sands family were among them. Others were transported to the extermination camp at nearby Belzec.
Otto wrote a long letter from Krakow, where he was attending a Nazi party congress.
His tone was positive, and everything was "lovely" at home in Lemberg
While Otto entertained Himmler in Krakow, Charlotte's parents and Otto's father visited her in Thumersbach.
Charlotte described her excursions around Thumersbach as "unbelievably lovely". They took hikes to the remote Schmittenhohe, lunched by a pond and swam. She felt "overwhelmed by the grandeur of nature".
As the family enjoyed their time in the mountains, the Grosse Aktion reached its conclusion in Lemberg.
Around this time, the New York Times reported charges against 10 leading Nazis, identified by the Polish government-in-exile, for crimes committed on the territory of Poland. The list included Otto's name.
The newspaper reported that upon his orders, 100 professors - Jews and non-Jews - from Jagiellonian University in Krakow had been sent to concentration camps; many had died, others had gone mad.
By 1943, the tide was beginning to turn.
In February, news reached Charlotte of the Nazis' defeat by the Red Army at Stalingrad.
The following year, as the Red Army moved in on Lemberg in the early spring, Charlotte responded by focusing on having fun.
She went horse riding and fox hunting.
Charlotte and the children left Lemberg and returned to Thumersbach. On April 17, with the Red Army less than 125km from Lemberg, Himmler drafted a new decree to be signed by Hitler that promoted Otto to the rank of SS-Gruppenführer. A single rank now stood between him and the Reichsführer.
"I will endeavour to warrant your extraordinary trust through exceptional performance," Otto assured Himmler. "I will handle the tasks that are given to me … and proudly meet them, aware of the special commitment that being a part of the Führerkorps of your SS entails."
That same spring, Himmler transferred Otto to Italy to serve as the head of the military administration in the north of the country, which was under Nazi occupation.
On July 27, 1944, Otto left Lemberg.
On July 26, Otto told Frank the district of Galicia was "practically lost".
Charlotte wrote three words in her diary: "Giving up Lemberg."
In September 1944, the Allies reached Rome and headed north.
Otto encouraged her not to feel despondent.
The family reunited in Thumersbach for Christmas that year, as British and American bombers flew overhead.
At the end of January 1945, Krakow fell to the Red Army.
On April 30, 1945, Hitler committed suicide.
On May 7, Charlotte received a call from Otto. He would try to make his way to Carinthia, to the mountains, he told her.
She asked him what she should do with his archives and he instructed her to destroy them.
The next day, the war in Europe ended.
Then, in the early summer of 1945, Otto disappeared.
What happened in the four years between his disappearance and his death in bed nine of a ward in the Santo Spirito hospital, within sight of St Peter's Basilica, is the subject of much of Sands's book.