Knowledge of these devices came from the observation of neutralized devices, from interrogations of the designers, from evidence located in terrorist safe houses, or from descriptions of the training terrorists received in their various camps. Most of these designs are in use in the Middle East and are still being taught to new recruits. New members are given classes on how to kill police officers and Explosives Ordnance Disposal personnel. These devices are currently being used by terrorists, freedom fighters, and drug traffickers.