For the first year of S-21's existence, corpses were buried near the prison. However, by the end of 1976, cadres ran out of burial spaces, the prisoner and family members were taken to the Boeung Choeung Ek ("Crow's Feet Pond") extermination centre, fifteen kilometers from Phnom Penh. There, they were killed by a group of teenagers led by a Comrade Teng, being battered with iron bars, pickaxes, machetes and many other makeshift weapons owing to the scarcity and cost of ammunition. After the prisoners were executed, the soldiers who had accompanied them from S-21 buried them in graves that held as few as 6 and as many as 100 bodies.