Tears come to Fortunee Benguigui's eyes as she sorts through the photographs of her three children killed in the gas chambers of Auschwitz by the Nazis.

"Other people forgive," she says slowly as she fumbles for a picture of her oldest son, Jacques, dressed up as a clown and entertaining a group of fellow Jewish schoolchildren. "But I cannot forgive. I suffered to have these children, and I do not want to die before the man who was responsible for their deaths is brought to trial."

About 200 miles away, in the eastern French city of Lyons, Klaus Barbie, a former Nazi SS officer accused of sending Benguigui's children to Auschwitz, sits in an isolated prison cell. He spends much of his time studying Homer's epic masterpiece, "The Illiad," as he prepares for his own trial on charges of crimes against humanity.

The three Benguigui brothers were among 44 Jewish children sent to Nazi death camps after the Gestapo raided their school in the village of Izieu in southwest France on April 6, 1944. The incident has become central to the state's case against Barbie -- who was known as the "Butcher of Lyons" because of his wartime activities -- and will figure prominently in the trial, which is likely to open toward the end of this year.

The trial will pit the determination of people such as Benguigui to see that justice finally is done against an array of legal, political and historical problems that arise from trying to prosecute someone for crimes committed more than four decades ago.

Public attention has focused on the case because of Barbie's dramatic expulsion from Bolivia in February 1983 after a post-war career that included collaborating with U.S. military intelligence in West Germany. Barbie is regarded by many writers and historians as a case study of a middle-level Nazi functionary who managed to escape from Western Europe after the war only to be brought back to the scene of his alleged crimes as an old man.

After wading through a welter of accusations against Barbie, 72, French investigating magistrates already have been obliged to narrow their case to a few specific charges that qualify as "crimes against humanity." This category excludes his actions against members of the wartime French resistance including their leader, Jean Moulin, whom he allegedly tortured to death in June 1943.

Under French law, Barbie can no longer be prosecuted for "war crimes" committed more than 20 years ago. But he can be charged with crimes against "humanity," -- that is, actions against noncombatants -- under a special exemption to the penal code adopted in 1964.

The 1964 exemption has enabled Barbie's defense lawyers to complain of "retroactive laws." They also claim that French society is guilty of double standards by pressing charges against Nazi war criminals while amnestying crimes perpetrated by French troops during the bloody eight-year colonial war in Algeria, which ended in 1962.

"The French forget what they did and think only about what the Germans have done," said Jacques Verges, Barbie's principal defense lawyer and a former French resistance fighter. "Barbarism existed before Hitler and went on after his death."

The Izieu children are crucial to the case against Barbie for two reasons. First, they were clearly noncombatants. Second, there is documentary evidence in the form of a telegram that links their deportation to a decision made by Barbie, then chief of the Gestapo in Lyons.

The telegram, which was produced at the Nuremburg trials of Nazi war criminals in 1946, turned up less than two years ago in the archives of the Jewish documentation center in Paris. Addressed to the Gestapo's department for Jewish affairs in Paris and signed by Barbie, it states that 51 Jewish adults and children "captured" at Izieu on April 6, 1944, would be transported to the concentration camps the next day.

For Serge Klarsfeld, a French lawyer turned Nazi hunter who is representing the families of deportees, the cable is documentary proof of Barbie's complicity in the deportation of Jewish children. He insists that it is irrelevant whether Barbie actually was present at the roundup of the children or their deportation to Auschwitz -- a point on which eyewitnesses disagree.

"The decision to send the children to Auschwitz was taken by Barbie. He claimed credit for it. The telegram also shows that it was a local initiative as it does not refer to any orders," Klarsfeld said.

In order to publicize the case against Barbie, Klarsfeld has prepared a glossy brochure describing how the school at Izieu was closed down and piecing together what became of the children. The brochure includes the text of a letter from Jacques Benguigui, then aged 12, to his mother on May 30, 1943, a year before his deportation.

"Oh mother, my dear mother, I know how much you have suffered for me," wrote Jacques just two months before his mother, too, was deported to Auschwitz. "I send you from afar my deepest best wishes from my little child's heart. Mother dear, being far from you, I did my best to make you happy:! When you sent me packages, I shared them with those who had no parents."

As Fortunee Benguigui recalls the horrors of Auschwitz 40 years ago, the soft Mediterranean sunshine floods through the lace curtains of her apartment. A small, withered lady with an Auschwitz tatoo on her arm, she is still half crippled as the result of horrifying medical experiments conducted upon her by Nazi doctors under the infamous Joseph Mengele.

"For someone who wasn't there, it is impossible to believe what we suffered. They ripped off people's skins to make wallets. Only those of us who have seen it know what it was like -- and we have a duty to talk about it so that it never happens again," Benguigui says softly.

Benguigui's first inkling that something dreadful might have happened to her three children came at Auschwitz when she spotted another Jewish boy wearing what appeared to be Jacques' pullover. "My spirit went dead at that moment," she recalls. Her fears were confirmed after the war when she heard the story of the Gestapo raid on Izieu.

Unlike Benguigui, some parents of children rounded up at Izieu cling to the hope that their loved ones might have survived the holocaust and are still alive somewhere.

For Klarsfeld, who says his primary concern is with the victims of Naziism rather than their persecutors, it is one more reason that Barbie must be brought to trial.

Jacques Verges, who is organizing Barbie's defense, sees the forthcoming trial as a unique opportunity to expose the hypocrisy of the "bourgeois state." A former Communist who represented Algerian nationalists during the war of independence, he wants to turn the tables on the prosecutors and transform the judicial proceedings into a trial of French society. Verges has threatened to use the judicial proceedings to unmask prominent French political figures who betrayed the resistance by cooperating with the Nazis during the war. He has also accused the Socialist government of seeking to delay the opening of the trial until after next year's parliamentary elections to avoid any political repercussions.

The defense lawyer's claims of political interference are dismissed by justice ministry officials who insist that preparations for the trial are going ahead of schedule. Although no formal date for the opening of the trial has yet been set, legal sources close to the court expect the case to open in a specially enlarged courtroom in Lyons in November.

Asked to explain why a left-wing lawyer who fought in the French resistance himself should want to defend a former Nazi, Verges said that he fully realizes that Barbie was not "an angel" but that it was impossible to prove the crimes that he is alleged to have committed. He described the telegram signed by Barbie reporting the deportation of the children of Izieu as "a fake."

"My concern is that by trying to punish a few Nazis we are denying democracy. It's better to let a few Nazis go free 40 years after the war than to deny democracy," he said.