Who is John Gacy from Without Conscience: The Disturbing World of the Psychopaths Among Us and what is their importance?

John Gacy was a Chicago businessman and serial killer who posed as a clown and killed 33 boys and young men. Gacy lured the boys to his home or kidnapped them while they were in town. At one point, one of Gacy's victims attempted to escape from Gacy's home when a few policemen visited. Gacy talked the police men into believing that the teenage boy was his lover and that they had had a quarrel. The policemen believed Gacy and did not help the boy.