During the Salem Witch Trials, a group of young girls accused numerous townspeople of witchcraft. One way to prove one's own innocence was to implicate others. Some people were probably genuinely afraid that witches were among them, while others were simply afraid of their fellow citizens, who might turn on them at any time. Either way, this contributed to the mass hysteria that swept the region at the time. This hysteria led people to do things they otherwise would not have done and kept logic and justice from preventing the deaths of innocent people.
The mass hysteria seen during the Salem Witch Trials was very similar to the hysteria seen during the Red Scare and McCarthyism. Again, people were so afraid of either Communism or their fellow citizens' accusations that they did things they wouldn't normally have done.