Camp inmates, Polish Jews caught hiding on the "Aryan side" of Warsaw, Polish political prisoners (Pawiak inmates) and Polish hostages captured during the street roundups were executed in the ruins of the former ghetto (which surrounded the camp) in 1943–1944. It is impossible to determine the exact number of victims of executions in the ruins, however historian Bogusław Tadeusz Kopka estimates that some 20,000 people were executed in the period. These included camp inmates, Polish Jews caught hiding on the "Aryan side" of Warsaw, and ethnic Poles. The ruins of the ghetto supplanted previous execution sites, which were in the countryside around Warsaw, such as the Kampinos Forest (the site of the Palmiry massacre). Proximity of the Pawiak prison and the isolation of the former ghetto from the rest of the city, made them – from the German perspective – a far more suitable place for mass killings.