What does Mma Notshi's character represent in The No. 1 Ladies' Detective Agency?

Over the course of the novel, Mma Notshi gives Mma Ramotswe information that she both wanted and didn't want - that the missing boy is both alive and whole, but that bones such as that which Mma Ramotswe believed belonged to the boy are readily available. In other words, bones are taken from children all the time. In that sense, Mma Notshi can be seen as representing, on some level, humanity's capacity for, and casual acceptance of, evil