"It's done while she's still alive because the more she screams, the more powerful the Muti's going to be," explains crime expert Kobus Jonker, gesturing at the picture of a mutilated six year old girl. He was the first South African to acknowledge Muti murders and has set up a special police unit to deal with it. But Muti murders are notoriously hard to prosecute. "My son will never sleep in peace," laments Salome Chokwe. Her ten year old boy, Sello, disappeared when out herding. By the time she found him it was too late. His hands, genitals, tongue and brain had been 'harvested'. Most practitioners use nothing more sinister than roots and leaves to make their Muti. But belief in the power of human body parts continues to fuel a demand for the 'other' type of Muti.