More than 800,000 Austrians joined the Nazi Party - out of a total population at the time of around seven million.
Heinrich Gross was a veteran Nazi, who had already enrolled in the Hitler Youth organisation in 1932, a year before the Nazis came to power in Germany - and six years before Adolf Hitler's annexation of Austria.
He is accused of complicity in the deaths of several hundred handicapped children in a Vienna clinic during World War Two as part of a Nazi programme of "purifying the Aryan race".
His immediate superior at the clinic was executed after the war.
But Heinrich Gross escaped punishment on a legal technicality.
He went on to become one of Austria's most respected, and highly-decorated neuro-psychologists and forensic experts.
He continued to experiment on the brains of the murdered children, which were carefully preserved at the clinic.
He became a trusted member of the Social Democrat party, which, together with the centre-right People's Party, dominated post-war Austrian politics.
Senility
He was still working two years ago.
On Tuesday, the judge suspended the trial, after claims that 84-year-old Heinrich Gross was afflicted with senility and Parkinson's disease.
The case illustrates many of Austria's problems with the Nazi era.
More than 800,000 Austrians joined the Nazi Party - out of a total population at the time of around seven million.
Many Austrians welcomed the German take-over, as a union of closely related German-speaking peoples.
Austrian companies are even now facing compensation claims from around 250,000 surviving forced labourers from various countries of Nazi-occupied Europe.
Victim or accomplice?
Already during World War Two, however, the Allied powers declared Austria to be a victim - rather than accomplice - of Nazi aggression.
It was a convenient piece of wartime propaganda - but one that allowed the Austrians subsequently to consign the Nazi era to a kind of oblivion.
Under the stifling, consensus-based post-war system, based on a Social Democrat-People's Party duopoly, mentioning the issue smacked of bad manners.
Of course, the Nazi past did not go away.
Many ex-Nazis found a home in the far-right Freedom Party.
Joerg Haider, until last month its controversial leader, began his career by appealing to the need of many older Austrians - including veterans of the notorious Nazi elite SS regiments - to be recognised as "decent fellows".
Mr Haider himself was born after the war.
But his parents had been enthusiastic and early members of the Nazi party.
He now says that Hitler was a terrible criminal.
But the Freedom Party's recent entry into government, which Mr Haider presents as a healthy break with the post-war duopoly, has led to Austria's boycott by its fellow EU governments.