John Demjanjuk is not an isolated case. German investigators have set their sights on other presumed Nazi war criminals, raising the question of how the law should deal with the aged accessories of the Holocaust.

The Central Office for the Prosecution of National Socialist Crimes (ZSTL) in Ludwigsburg, near Stuttgart, already has its sights set on four other men who may have committed murder or been accessories to murder on behalf of the Germans, and who, like Demjanjuk, subsequently emigrated to the United States.

A preliminary investigation is now under way against Ivan Kalymon, 87, who lives in Michigan. Kalymon once worked for the Germans in Lemberg, now Lviv, Ukraine, as a member of the Ukrainian Auxiliary Police. In August 1942, he wrote a short-handwritten note to his superiors to report on a mission. The document reads: "I employed my weapon in the line of duty during the 'Jewish Action' on 8/14/1942, at 7 p.m., using four rounds of ammunition, wounding one person and killing another."

US authorities consistently limit their actions to revoking the US citizenship of suspected Nazi war criminals and then deporting them to European countries. The legal hurdles for taking these steps are relatively low: All it takes is proof that a suspected war criminal lied about his past upon immigration to the United States.

The Americans have never put any suspected Nazi war criminals on trial, even though the Nazis' victims included American Jews who lived in Europe or happened to be there at the time. Otherwise, US courts could have faced a large number of cases. Historians and legal experts estimate that up to 10,000 Nazi collaborators emigrated to the United States during the chaos of the first few postwar years.

The Americans are not the only ones to have shown little interest in bringing Hitler's helpers to trial. There has also been a lack of commitment on the part of Europeans. For instance, the United States would have extradited suspected concentration camp guard Demjanjuk to Ukraine or Poland long ago if those countries had shown an interest in prosecuting him.

The failures of the German judiciary have been the most grievous, however. Even as German investigators are now focusing their attention on the Nazis' foreign henchmen, German accessories to murder were more or less allowed to escape punishment for years. Since the end of the war, German courts have investigated more than 100,000 cases, but only 6,500 of the accused were ever sentenced. "While senior government officials, officers and commanders enjoyed their retirements in peace," says Christiaan F. Rüter, an Amsterdam criminal law professor, "this old man is now expected to pay for everything." Rüter is referring to Demjanjuk.