Wachawi

Anyone studied the Wachawi sect Vodoun of Pemba and Zanzibar Islands? Most of these Island areas are owned by Tanzania, off The East of Africa in The Indian Ocean and are 99% Islam. I have seen minimal reference and book notes over years as to a magick, essentially, in legend.
One reference came supposedly from a book kept at Harvard. Another was excerpts from a study of African religion that was made available on the web. These were passing references to other references apparently. The sect was known to have tremendous underlying influence in the cultures and may have been linked specifcally to animation of corpses beyond the normal legends of other Vodoun, East Africa, etc… My gut tells me this maybe an underlying influence of wealthy ruling class and hidden well behind the veil of Islam. Wishful thinking? Also, pointing out, again, this is of EAST Africa, not referring to West Africa as usually observed. Regards.