Along Came a Spider - James Patterson

The whole nation was in uproar when two celebrity rich kids were kidnapped – and then one of them was found dead. For such a high-profile case, only the top people would do: Alex Cross, a detective with a PhD in psychology, and Jezzie Flanagan, a fast-rising young Secret Service agent. Yet even they were no match for the killer.

He could switch from blood-crazed madness to clear-eyed sanity in an instant. But was he the helpless victim of a multiple-personality disorder

– or a brilliant, cold-hearted manipulator?