Invisible Executioner - S4.E3

It's common knowledge that crocodiles and hippos are deadly predators in Zambian waterways, but it seems there's another monstrous beast stalking the treacherous Zambezi River. The locals call this river monster "the Mazunda" but Jeremy Wade is unfamiliar with any fish by that name. Will he uncover what the sinister creature — said to be able to swallow a child — really is?