BERLIN — A 92-year-old man who served as a border guard in Adolf Hitler’s elite Waffen-SS troops went on trial on Monday on charges that he shot and killed a Dutch resistance fighter in the final months of World War II. His prosecution is part of a German effort to bring aging Nazis to justice before it is too late.

The trial of the onetime guard, Siert Bruins, in the Hagen state court in western Germany, is part of a wider attempt across Europe to prosecute former Nazis who have not drawn much attention from a legal system that focused mainly on higher-level officers. Mr. Bruins is one of several men accused of serving an important but largely invisible role in Nazi atrocities to face charges in recent years.

Mr. Bruins, who was born in the Netherlands but acquired German citizenship while serving with the Nazis, is accused of killing Aldert Klaas Dijkema, a Dutch resistance fighter, on the night of Sept. 21, 1944.