AACHEN, Germany, March 3 — A German prosecutor called for a life prison sentence for a former Nazi SS officer involved in the deaths of some 50 Dutch civilians during World War II.

Heinrich Boere, 88, is on trial for the 1944 wartime killings of more than 50 Dutch civilians in retaliation for attacks carried out by the resistance.

Boere was convicted in absentia in the Netherlands shortly after the war for his participation in the so-called Silbertanne killings. However, he was not extradited because he was a German national.

The Dutch newspaper NRC Handelsblad said Wednesday that prosecutor Ulrich Maass requested the life term at a hearing in Aachen Tuesday. There was no immediate ruling by the judge.