Chief Judge Klaus Kabisch in the Neubrandenburg state court explained on Tuesday that brothers Walter and William Plywaski – themselves Auschwitz survivors – could not join the trial because the date of their parents’ death at the camp falls just outside the time frame of the indictment – a one-month period in 1944.

The brothers had been initially approved as co-plaintiffs, after a higher court rejected Kabisch’s arguments about the time limit.

Meanwhile, the trial has been delayed over concerns about the mental and physical health of the defendant. Last year, Zafke’s son pleaded with the court to leave his father in peace.

Critics suggest that Judge Kabisch may be trying to delay the procedure. According to German news reports, in an unprecedented move,  prosecutors have filed several petitions – in vain – to have Kabisch

removed from the case due to bias.

Attorneys for the Plywaskis – Thomas Walther and Cornelius Nestler – said they would appeal to have the brothers reinstated as plaintiffs. Walther and Nestler also are considering filling bias charges against the court.

Zafke faces charges of accessory to the murder of 3,681 people. In his capacity as a medic, he reportedly witnessed arriving prisoners being sent to die in the camp’s gas chambers.

Germany’s Central Office for the Investigation of National Socialist Crimes in Ludwigsburg made a major push to identify former death camp guards after the conviction of John Demjanjuk in 2011 for his role in the murders of nearly 30,000 Jews in the Sobibor death camp in Poland. That case set the precedent that being a guard at a death camp was sufficient to prove complicity in murder.