Frederik Pohl 
Plague of Pythons 

On Christmas the world’s freedom died. Every man, woman and child lay in the grip of fear, for no one knew at what moment his nearest friend or a casual stranger might suddenly be possessed by some brutal mind … and begin to murder and destroy. For Chandler it was worse than for most. He was both victim and executioner. He had suffered himself, and he had committed a violent crime while under the strange domination. Accusing of hoaxing he was driven from his home. He wandered the world and found it smashed like a spoiled child’s plaything – now Chandler was in the very presence of the destroyers! But what could one person do against such power? – the power of gods!