Witch hunt

A witch hunt is a search for witches to capture. Witch hunts often involve moral panics or mass hysteria. They were much more common in the past than they are today. Many different groups participated in witch hunts, including Christians.
History.
Witch hunts were most common in Europe from about 1480 AD to 1700 AD, during the Protestant Reformation and the Thirty Years' War. Tens of thousands of “witches” were executed during this period. Around the same time, there were many witch hunts in America, such as the Salem Witch Trials.
Witch hunts today.
Today, there are fewer witch hunts. Most countries no longer have laws against witches. 
Most witch hunts today happen in South America, Southeast Asia, and Africa. Societies where witch hunts happen have a strong belief in magic. In many cases, these are instances of lynching, and burning a person. Witch hunts are regularly reported from much of Sub-Saharan Africa, from Saudi Arabia and from Papua New Guinea. 
The UNHCR say that such witch hunts usually are a massive violation of human rights. Most of the accused are women and children but can also be elderly people or marginalised groups of the community such as albinos and the HIV-infected. These victims are often considered burdens to the community. As as a result they are often driven out, starved to death, or killed violently, sometimes by their own families in acts of social cleansing. The causes of witch-hunts include poverty, epidemics, social crises and lack of education. The leader of the witch-hunt, often a prominent figure in the community or a "witch doctor", may also gain economic benefit by charging for an exorcism or by selling body parts of the murdered.
In metaphor.
The term "witch hunt" is also used as a metaphor to describe a search for enemies in which people are accused without any real evidence. For example, during the Cold War, United States Senator Joseph McCarthy led a hunt for communists in American government and society. He accused many people, but eventually found no communist spies. McCarthyism is often called an example of a modern “witch hunt.”