A mob armed with machetes, stones and knives killed seven people accused of practicing witchcraft in southern Tanzania (search), a regional police chief said Thursday.

Villagers said the alleged witches cut off the sexual organs of dead villagers and used them to concoct charms intended to bring good harvests and fortune.

About 22 villagers and local leaders appeared in a magistrate court Wednesday on charges of killing the seven — five men and two women from three villages, said Omari Maganga, police chief for the southern Iringa region.

Police investigations indicated village leaders and other local officials ordered the killings after villagers informed on the victims, Maganga said.

Belief in witchcraft (search) is common throughout rural Tanzania.

A 2002 report by the U.N.'s World Health Organization (search) said an estimated 500 elderly women accused of witchcraft — often connected with an event like crop failure — are murdered every year in Tanzania.

Others have killed relatively wealthy villagers they accused of being witches and then claimed their property.

The killings have also been linked to a cross border trade in human skins that are used in witchcraft. Some people believe human skin protects a home from demons and spirits and when used in special rituals can increase harvests and lure clients to shops and other businesses.