Who is Mma Notshi from The No. 1 Ladies' Detective Agency and what is their importance?

Mma Notshi is the wife of the so-called "witch doctor" that Mma Ramotswe believes is connected to the disappearance of the missing boy. Sent to her by Gotso, Mma Ramotswe manipulates Mma Notshi into revealing the truth of the boy's whereabouts. Along the way, Mma Notshi gives Mma Ramotswe information that she both wanted and didn't want - that the 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 (see "Topics for Discussion - In what way are Mma Notshi ..."