Every genocide must have what you might call its “doctor,” its cruel and merciless master of death, its unwavering murderer. These men put the ideologies to work. They systematically dispose of the enemy, surgically remove it. But few of them are political idealists. They are more mercenary than philosophical, more calculating than soulful. Before the UP came along, Colombia had had its share of “doctors.” During La Violencia, a paramilitary known as “Blackblood” once drank several liters of his dead adversary’s blood to illustrate his resolve; another known as “The Butcher” hung his victims in a tree before cutting off their faces. During the period of the UP, there was a “doctor” called Black Vladimir whose specialty was chopping his victims to pieces before disposing of them in a river.