BERLIN (AP) — John Demjanjuk attends most sessions of his trial in a hospital bed set up in the courtroom, wearing dark sunglasses and a hat pulled down over his face.

The case of the retired Ohio autoworker accused of serving as a Nazi death camp guard — which resumes next week after a monthlong summer break — broke potentially precedent-setting ground when it opened last year.

But it has become increasingly dominated by the 90-year-old defendant's failing health.

Nazi hunters have taken keen interest in the Demjanjuk saga because it's the first time German authorities have prosecuted such a low-ranking suspect on the premise that, even without evidence of a specific crime, simply working at a death camp was enough to be an accessory to murder.

German prosecutors have since opened investigations of two others on a similar basis, both men who were called as witnesses at the Demjanjuk trial — and a conviction could open the way to scores of more such cases.

However, such questions have become secondary to the endless health complications of the man accused of having served in occupied Poland's Sobibor death camp.

Demjanjuk suffers from bone marrow disease and other medical problems, and nearly a dozen out of a scheduled 57 court dates have been canceled so far for health reasons. The health issues have slowed the proceedings to a crawl as the judges struggle to balance Demjanjuk's needs with its schedule of evidence and witnesses.

Hearings were originally scheduled through May, then extended into December, and now most observers don't anticipate a verdict before well into 2011.

"If Demjanjuk is well enough, I expect more dates until Easter — I do not expect an end of the trial before that," said Stefan Schuenemann, who represents two Sobibor survivors as co-plaintiffs in the trial, as allowed under German law.

Ukrainian-born Demjanjuk stood trial in Israel in the 1980s on charges he was the notoriously brutal guard "Ivan the Terrible" at the Treblinka extermination camp. He was convicted, sentenced to death — then freed when an Israeli court overturned the ruling saying the evidence showed he was the victim of mistaken identity.

Demjanjuk was deported from the U.S. in 2009 to stand trial in Germany, charged with being an accessory to the murders of 28,060 people at Sobibor.

He again argues he is being mistaken for someone else, and denies having served as a guard for the Nazis anywhere. His attorneys have argued he was one of Hitler's victims himself: first wounded as a Soviet soldier fighting German forces, then captured and held as a prisoner of war under brutal conditions.

Even if the judges find there is enough proof that Demjanjuk was at Sobibor, they still have to accept the prosecution's argument that being present at the camp was akin to participation in the Holocaust — no matter what his job was.

"There must be a limit," Schuenemann said, explaining the difficulties the prosecution faces. "How near must you be to the killing? You pushed Jews into the gas chambers or you just guarded the fence? These are questions that have to be answered in the trial and it's not easy ... where does responsibility start?"

In court, Demjanjuk has never shown any reaction to testimony — although he speaks with his attorneys and translator during breaks. His son, John Demjanjuk Jr. points to the fact that he has needed nine blood transfusions since coming to Germany last May as treatment for dangerously low hemoglobin levels.

"He is under constant medical care and while he is willing, he is unable to follow the proceedings and is no more fit for trial than 99 percent of the Germans currently living out their last days in nursing homes," he said.

But Barbara Stockinger, a spokeswoman for prosecutors in Munich, dismissed concerns that the trial might soon be unable to continue.

"I am no doctor... but there is always a doctor present and he has said that he is fit for trial," she said.

At one point in July, Judge Ralph Alt ordered Demjanjuk into court, saying that prison doctors had determined he was fit but that he was refusing to attend because he had "no interest."

The defense contests that, saying Demjanjuk was legitimately ill, and filed a motion during the summer break, which has not yet been ruled upon, asking for Alt's removal from the case.

Efraim Zuroff, the top Nazi hunter at the Wiesenthal Center, said health issues come up in most prosecutions now — more than 65 years after the end of World War II with even the youngest defendants now in their 80s. He said it takes a "moral resolve" to continue with them.

"It's too easy to walk away from this," he said in a telephone interview from Jerusalem.

"I think so far the judges and prosecution have not given in and rightfully so. The doctors say he can continue, he has to continue."

Demjanjuk is accused of serving as a "Wachmann" or guard at Sobibor, subordinate to German SS men.

Demjanjuk's family questions why his has emerged as the test case — and has suggested that trying a Ukrainian helps deflect blame from Germany.

"It is shockingly wrong for the Germans to have ignored bringing their own people to trial for so many years and to now break new legal ground against a 90 year-old ill man who himself was a POW victim of the Germans," Demjanjuk Jr. told The Associated Press in an e-mail.

The trial has already served to refocus the attention of prosecutors on two men who have lived in Germany for years, but were never pursued.

In July, prosecutors charged 89-year-old Samuel Kunz, an ethnic German, of accessory to the murder of 430,000 Jews while he was allegedly a guard at the Belzec death camp, and with 10 counts of murder for unspecified "personal excesses." Kunz was supposed to testify at the Demjanjuk trial but then backed down after learning he was under investigation himself.

Prosecutors are also investigating the case of another Ukrainian, Alex Nagorny, who testified as a witness at the trial. They are currently trying to determine whether he is the same person as a Nagorny implicated by witnesses as a guard who took part in killing people in Treblinka.

Since the Demjanjuk trial started, two other elderly suspects under investigation have died before their cases could be brought to court.