Soon after the British liberators entered the camp its function changed. The camp was subjected to Military Authority. The German military personnel had to turn in their armament in Kamp Amersfoort. Under supervision of the Military Authority research was done to what really happened in the camp. Also the victims who were buried in the surroundings were identified. During this research the extent of the atrocities that happened in this small wooded plot became clear. The DIB (Dienst Identificatie en Berging, an organisation of the Ministry of Defence that was concerned with exhumation and identification) was charged with the exhumation of several hundreds of victims. On June 22nd 1945 the first mass grave op the PDA was opened. It was the final resting place of forty -nine victims buried at the end of the shooting range opposite of the PDA. The Dutch Red Cross supervised the exhumation by the DIB of these forty nine victims. Extensive help was given by dr. C.J. van Ledden Hulsebosch of the coroners office in Amsterdam, Mr. P.H. van Haselen, a local undertaker and dr. Dekker of the public health authority in Amersfoort. Detectives of the POD (Politieke Opsporings Dienst, Political Tracing Service, a department that traced war criminals) were closely involved with the operations, just as with the exhumations that would follow.