A witch-hunt or a witch purge is a search for people who have been labelled witches or a search for evidence of witchcraft, and it often involves a moral panic or mass hysteria...

In current language, "witch-hunt" metaphorically means an investigation that is usually conducted with much publicity, supposedly to uncover subversive activity, disloyalty, and so on, but with the real purpose of intimidating political opponents.

https://en.wikipedia.org/wiki/Witch-hunt