Mass graves exist.: "... died or murdered 22,000 prisoners of war and were buried in 32 mass graves in the outskirts of the camp." [November 2003] http://www.zchor.org/poniatowa/poniatowa.htm
Forced Labour and Prisoner of War camp in Poniatowa near Lublin was established in September 1941 for Soviet POWs. By December, 24,000 Soviet prisoners were interned in conditions so harsh that hundreds died daily; by early spring 1942, some 22,000 prisoners had died or had been executed. During that summer, the German army gave the SS control of the camp that turned it into a forced labor camp for Jews. The first Jews arrived in October 1942 with about 1,500 Jews were interned by January 1943. After the Warsaw Ghetto uprising in April 1943, 16,000-18,000 more Jews were brought. 10,000prisoners labored in a textile factory transferred from Warsaw Ghetto. The rest did various outdoor jobs. Hundreds were executed or tortured to death by the SS staff and the Ukrainian guards. On November 4, 1943, the Germans began destroying Poniatow. A one-day massacre called "ERNTEFEST" murdered about 15,000 Jews. Resistors were burnt alive in their barracks. Only a few survivors escaped before the camp was totally liquidated. [June 2009]