The prosecutors in the case of 90-year-old John Demjanjuk said on Tuesday that he should serve six years in jail for helping to kill 27,900 Jews during the time he allegedly served as a guard in a Nazi death camp.

AFP quoted German prosecutor Hans-Joachim Lutz as saying during his summary of the high-profile war crimes case, that Demjanjuk had participated willingly in the Holocaust. Lutz added that there is “no reasonable doubt” of Demjanjuk's involvement in the crimes committed at the Sobibor camp in Nazi-occupied Poland during March and September 1943, when he allegedly was there.

Demjanjuk was formally charged by Germany in 2009 after being extradited by the United States, where he had immigrated after the war. The Ukraine-born Demjanjuk claims he is innocent of any killings and that the case against him is one of mistaken identity. He claims he was a Red Army soldier who was captured by the Germans and spent the war as a prisoner of war.

However, evidence obtained by the United States Justice Department showed a photo ID that shows Demjanjuk was a guard at Sobibor. The ID also reveals that he was credentialed at Trawniki, a special SS training facility for Nazi personnel that was located in German-occupied Poland. The prosecution in the case argued that after his capture, Demjanjuk volunteered to serve the Germans as a guard.

On Wednesday, relatives of people who were killed in Sobibor and their lawyers said in closing statements at Demjanjuk’s trial that the evidence shows he was a guard there and he should be convicted as an accessory to murder, the Associated Press reported.

The relatives of those killed in Sobibor, as well as three survivors, joined the trial as co-plaintiffs, as allowed under German law.

“I hope that before I die I will get justice from this trial,” said Eastchester, New York-resident Aleida Keesing, who said in a statement sent to the Munich state court that both of her parents, as well as her brother and his family, were killed in Sobibor in 1943, when Demjanjuk is alleged to have been a guard there.

Ralph Erman of New York City recalled in another statement that was read aloud in court, a postcard that his family received from his father, who was killed in Sobibor along with his mother.

“Tomorrow we will start our long journey to the unknown,” wrote Erman’s father before he was transported by train from Holland to the death camp.

“We should ensure that all of those who are still alive who took part, even if they had only a small role, are brought to justice,” Erman wrote in his statement.

Last month Demjanjuk threatened to go on a hunger strike unless the court allows him to present KGB documents which he claims will exonerate him.

The documents in question are transcripts of a 1985 interview with former Sobibor guard Ignat Danilchenko, who told Soviet officials that none of the Ukrainian auxiliary guards were used by the Nazis inside the camp.

The court rejected the requests to push for the file, saying the claim by the defense that there is relevant evidence in it is merely a “hypothesis.

Demjanjuk’s trial will resume on April 13, at which point more statements from co-plaintiffs will be read, followed by the defense’s closing arguments. A verdict in the case is expected in mid-May.