How did the ceremony of the witch hunt begin?

In Chapter Ten, Gagool leaps up from her place at Twala’s feet and calls for the ceremony to start. At Twala’s command, the soldiers begin a loud song covering the various phases of life, from young love to death. Then a group of aged, white-haired women, their faces painted in white and yellow stripes, come forth and declare their presence to Gagool. The old wise woman sets them loose upon the people to find those who think evil toward Twala. The women dance for a while, crying out their ability to locate the “witches,” then begin touching men with forked sticks. Each man touched is pinned by his neighbors and stabbed through the heart by Twala. To ensure death, each man speared is also clubbed violently on the head. Twala counts the victims (whom he calls “sacrifices”) and eventually reaches over one hundred.