A German court put John Demjanjuk on trial Monday to face charges of being an accessory to the murder of 27,900 Jews at a Nazi death camp, and his lawyer immediately accused the court of bias. The 89-year-old retired Ohio autoworker arrived at the opening of the trial in a wheelchair to face the final chapter of some 30 years of efforts to prosecute him, wearing a navy baseball cap and covered in a light blue blanket. After the first 90-minute session, Demjanjuk was returned to the courtroom lying flat on his back on a gurney, covered in blankets. Doctors who had examined Demjanjuk before the second session began said he had complained of serious pain and was given a shot. They ordered the session be cut short, and it wrapped up 30 minutes later. Demjanjuk's attorney had opened the proceedings by filing a motion against the court's judge and prosecutors, accusing them of treating the Ukrainian-born Demjanjuk harsher than Germans who ran the Nazi's Sobibor death camp in occupied Poland. Lawyer Ulrich Busch charged that the case should never have been brought to trial. He cited cases in which Germans assigned to Sobibor - where prosecutors allege Demjanjuk served as a guard - were acquitted. "How can you say that those who gave the orders were innocent ... and the one who received the orders is guilty?" Busch told the court. "There is a moral and legal double standard being applied today." Demjanjuk was deported in May from the United States to Germany, and has been in custody since then. He could face up to 15 years in prison if convicted. A doctor who examined Demjanjuk two hours before the trial began said his vital signs were all stable. Demjanjuk's family, however, says he is terminally ill. His trial has been limited to two 90-minute sessions per day. Demjanjuk kept his eyes closed throughout the proceedings and remained mute in response to the judge's questions about his personal details. He repeatedly opened his mouth, apparently wincing in pain. Efraim Zuroff, the top Nazi-hunter at the Simon Wiesenthal Center, said it was important the trial was finally taking place, but felt that Demjanjuk may have been trying to look more ill than he was. "He has a vested interest in appearing as sick and as frail as possible. And he's going to play it up to the hilt," said Zuroff, who attended the opening. Demjanjuk became a household name in the 1980s when he was extradited by the United States for trial in Israel on charges that he was the notoriously brutal guard at the Nazi's Treblinka death camp who earned the moniker "Ivan the Terrible" for his deeds. He was convicted in 1988 of war crimes and crimes against humanity, and spent seven years in prison until Israel's Supreme Court in 1993 overturned the conviction. It ruled that another person, not Demjanjuk, was actually "Ivan the Terrible." Demjanjuk, a former Soviet Red Army soldier, is now accused of volunteering to serve as a guard under the SS after being taken prisoner by the Nazis in 1942. According to the indictment, he served as a simple "wachmann," or guard, under the SS. As such, he is the lowest-ranking person to go on trial for Nazi war crimes. The prosecution argues that, even with no living witnesses who can implicate Demjanjuk in specific acts of brutality or murder, just being a guard at a death camp means he was involved in the Nazis' machinery of destruction. Before that, however, the prosecution must prove that Demjanjuk, who is being tried in Munich because he lived in the area briefly after the war, really did serve at the camp. Demjanjuk questions the authenticity of one of the main pieces of evidence - an SS identity card that prosecutors say features a photo of a young, round-faced Demjanjuk and that says he worked at the death camp. He claims to be a victim of mistaken identity and says he was a Red Army draftee from Ukraine captured during the battle of Kerch in the Crimea in May 1942 and himself held prisoner until joining the so-called Vlasov Army of anti-communist Soviet POWs and others. That army was formed to fight with the Germans against the encroaching Soviets in the final months of the war. Some of the most damning evidence comes from statements made by Ignat Danilchenko, a now-deceased Ukrainian who once served in the Soviet Army and was exiled to Siberia following World War II for helping the Nazis. In 1979, he told the Soviet KGB that he served with Demjanjuk at Sobibor and that Demjanjuk "like all guards in the camp, participated in the mass killing of Jews." But there are inconsistencies in the Danilchenko statements, and the defense questions their validity. The trial will resume Tuesday. Court sessions are scheduled through May. If convicted, Demjanjuk could be given credit in sentencing for some or all of the time he spent behind bars in Israel. Even if he is acquitted, however, Demjanjuk likely will have to remain in Germany as he has been stripped of his US citizenship.