On Monday, a 95-year-old former medical orderly at the Auschwitz death camp will return to the courtroom in the northeastern lakeside town of Neubrandenburg, accused of more than 3,600 counts of accessory to murder.
The case against Hubert Zafke, who is wheelchair-bound, has been suspended four times since the first hearing in February because of concerns over his health.
But months into the attempt to prosecute him, no evidence has been heard and the trial hangs by a thread.
A parade of doctors have been quizzed in court about Zafke's mental health, with each reaching a different conclusion.
The hearings have taken a sometimes farcical tack, delving into his life in a rural village: Does he sometimes forget to feed his cats? Did he give his sheep too much to eat?
"While judges and experts review his daily life, the prosecutors stare into space," said newspaper Die Welt.
The International Auschwitz Committee, a group representing camp survivors, has also sharply attacked Germany's handling of the case, saying the court was hurtling "between sloppy ignorance and complete disinterest" in a resolution.
The question of whether Zafke is fit to stand trial is also due to be addressed again by the court this week.
Anne Frank's train
The wizened Zafke is the fourth former concentration camp worker in the dock in this latest series of trials for Nazi-era crimes, following John Demjanjuk in 2011, Oskar Gröning in 2015 and Reinhold Hanning this May - all convicted before solemn, packed courtrooms of complicity in mass murder.
The Demjanjuk case set the legal precedent that defendants could be sentenced for having worked at concentration camps where atrocities were committed without proof of specific crimes by them.
The charges against Zafke focus on a one-month period in 1944 when 14 trains carrying prisoners - including the teenage diarist Anne Frank - arrived at Auschwitz-Birkenau.
Frank, who arrived in Auschwitz with her parents and sister, was later transferred to another camp, Bergen-Belsen, where she died in March 1945, just two months before the Nazis were defeated.
Prosecutors have said Zafke was aware that the site in Nazi-occupied Poland was an extermination camp, and have accused him of at least 3,681 counts of accessory to murder.
But victims' lawyers are growing increasingly frustrated.
"The co-plaintiffs have abandoned all hope that a trial that is anything other than a farce will actually start one day under this presiding judge," their attorneys, Thomas Walther and Cornelius Nestler, said in a statement last week.
'A fig leaf'
Both the state and the victims have tried twice to have the judge, Klaus Kabisch, recuse himself - a motion that will be addressed on Monday.
They argue that Kabisch is biased because he had been unwilling to start the trial in the first place due to Zafke's poor health, before being overruled by a higher court.
"The justice system has rarely offered a spectacle that is so undignified," influential news weekly Der Spiegel wrote, noting the sharp contrast with the previous three trials.
Those cases were hailed for providing a degree of catharsis for aged survivors, even if they shed little new light on the known facts of the Holocaust.
As the proceedings have stalled, a media war has gathered pace, with a lawyer for Zafke, Peter-Michael Diestel, blasting a "humanely troubling" and "politically dubious" effort to convict his client.
"I consider it extremely distressing that the German justice system, which has only spottily addressed the Holocaust, is trying to create a fig leaf for itself with this kind of trial," he said in February.
More than 70 years after the prosecution of top Nazis began in Nuremberg, Germany is racing against time to try the last Third Reich criminals.
Some 1.1 million people, most of them European Jews, perished between 1940 and 1945 in Auschwitz before it was liberated by Soviet forces.