Pop Goes the Weasel (1999) is the fifth novel in the Alex Cross series written by James Patterson.
The book begins by introducing the villain, Geoffrey Shafer. He is a well-dressed and wealthy man who lives in Kalorama, Washington, D.C. and drives a Jaguar XJ12. In the beginning, he rushes into oncoming traffic causing a commotion, before a police officer pulls him over and asks him for some identification. This is when the reader finds out he is a British Diplomat who has diplomatic immunity.
As Geoffrey feels he is losing control, he decides to play a fantasy game called the Four Horsemen, in which he takes on the character of Death. As the game begins, he drives to the red light district, picks up a prostitute and e-mails the other Horsemen.
All four of them killed people in their area, but Shafer was more out of control. During their time in Bangkok they all murdered prostitutes.