Hunting for witches

The most famous hunting for witches were the Salem witch hunts in the early United States where a number of women were accused of being witches, and burnt at the stake. However, there are still many cultures where there is a belief in witches and ghosts; this turns out to be ghastly in many situations where somebody is accused of being a witch, and in a mob situation, the hapless person is killed in one way or the other; this can actually be used for person retribution against the accused - what better way to get someone out of the way and yet not be accused of anything:

In late May, news outlets in Kenya told the story of 15 people, mostly elderly women, who were murdered in a witch hunt near the town of Kisii. The killings shocked the nation. Villagers said more than 100 people gathered machetes and knives and stormed the village of Kegogi after midnight.
Belief in witchcraft is strong in this part of Kenya. A few days before the incident, a group of schoolchildren reportedly found a book in their school that listed all the people in the community who would soon die and the witches who would be responsible. The area is one of the most populated rural areas in Kenya. Over the years, farming plots have been divided and subdivided. Omache and others say they believe witch hunts are about greed and vendettas in a place where almost everyone struggles to survive.

In all cases, the reason has either to with a fear that turns into a mob action, or with the attempt to get somebody out of the way.