If the tearful pleas of the man who pulled the trigger are to be believed, it was no more than a tragic accident. When Marcel Nel, a white South African farmer, shot at a dark shape rustling in the long grass at dusk on his neighbour's plot, he thought that he had at last caught the dog that had been terrorising his animals. In another stark example of the racial tensions that still haunt South Africa, many are convinced that it was a deliberate, racist murder.