By then, the Germans had already destroyed evidence of the camp's existence, leaving no prisoners behind.[8] One of the camp survivors, who was fifteen years old at the time, testified that only three Jewish males had escaped successfully.[2] The Holocaust Encyclopedia counted seven Jews who escaped; among them was the author of the Grojanowski Report, written under an assumed name by Szlama Ber Winer,[3] a prisoner in the Jewish Sonderkommando who escaped only to perish at Bełżec during the liquidation of yet another Jewish ghetto in German-occupied Poland.[4] In June 1945 two survivors testified at the trial of camp personnel in Łódź.