 His testimony along with that of the few other witnesses was critical to prosecution of camp personnel and other Nazi officials, because of the destruction of evidence by the Germans of their mass extermination of Jews in Chełmno.At the age of fifteen, Srebrnik testified in June 1945 in the Polish trial of Chełmno personnel.He testified again about Chełmno in the 1961 trial of Adolf Eichmann in Jerusalem, and in the Chełmno trials in Germany (1962–1965) of the former SS men from the SS Special Detachment "Kulmhof".