Of the hundreds of offenders, few are still alive. Survivors' memories are fading. The crimes, committed by Nazi forces retreating northwards across Italy, date back to before most Italians were born.
Marco De Paolis, the man leading Italy's top probe into Nazi war crimes obscured for years, faces a race against time.
"In the first case we took to trial, earlier this year, four officers were accused. Only one was still alive, and he died on the second day of the trial," said De Paolis, sitting at a desk piled high with files and reams of typed paper.
"The case was closed, of course. We cannot put the dead on trial."
When De Paolis took the military prosecutor's job at the naval base of La Spezia 15 years ago, he hoped to enjoy some yachting in his free time.
Instead, he has been overwhelmed by eyewitness accounts of murders to avenge partisan attacks, brutal shootings and attacks on villages placed along the so-called "Gothic Line" of defense that cut across Italy, from south of La Spezia to the Adriatic.
Altogether, historians estimate that some 7,500 people died in such assaults.
"People were crammed into barns or stables and machine gunned and then their bodies were set alight," he said. "In a small space, 50, 60 people were put together and machine gunned. Some were lucky enough to be covered by the bodies of others."
The crimes, carried out in the last two years of World War II, came to light a decade ago, when a filing cabinet packed with witness statements was found in Rome.
According to recent historical studies, Allied forces had initially intended to stage an "Italian Nuremberg" -- a version of the trials which involved top Nazi officials in 1945 and 1946.
But the plans were shelved in 1947, and by the late 1940s only a dozen court martial proceedings were closed.
The "cabinet of shame" was turned against a basement wall for almost five decades, presumably under political pressure from authorities who felt that opening up wartime wounds would have upset postwar Italy's delicate political balance.
It was eventually found in the 1990s by magistrates investigating former SS captain Erich Priebke over the slaughter of 335 men and boys at the Ardeatine Caves south of Rome.
The cases relating to aggravated homicide -- for which there is no statute of limitations under Italian law -- were reopened, investigated and will all eventually be brought to court.
Around a third of the files ended up in La Spezia, where the military court's constituency includes the regions crossed by the "Gothic Line".
It was on that line of defense, along the top of the Apennines, that the worst massacres were carried out, including on the village of Marzabotto, where some 800 people died, and Sant'Anna di Stazzema, where the SS killed 560 people.
"Survivors who were children at the time tell us what happened, helping us to prove these events took place," said De Paolis in his office in La Spezia, a town of quiet sun-drenched piazzas south of Genoa.
"It's one thing if there is a battle between two divisions and some civilians are caught in the middle and die. It's another if a division goes into a village, sets fire to it and kills every man, woman and child."
Six men are currently on trial for the massacre of Sant'Anna, a Tuscan village near Pisa.
The case, one of the most notorious wartime massacres, is an example of the difficulties De Paolis faces -- none of the six ex-soldiers, all in their 80s and living in Germany, will travel to the trial. They are unlikely to be extradited or to serve a prison sentence.
RSS