In the early 1970s Houston was haunted by evil in the form of a man named Dean Corll. The prominent and well-liked candy-maker showed a genial face to the city, but in reality was a murderous and sadistic rapist who claimed the lives of at least 28 young boys and men until he was shot down by his own accomplice.

That accomplice was Elmer Wayne Henley, 17, who started out as a potential victim himself but became Corll's personal procurer and executioner for two insane years. Now, a young Houston filmmaker, Joshua Allan Vargas, is bringing to life Henley's tale in a new movie called In a Madman's World.

Vargas spent a year interviewing Henley in prison, where he is serving six life sentences for his part in aiding Corll. The director even obtained Henley's actual clothes and effects, held in forgotten storage by his family for decades for his shoots. The resulting story is a shocking and disturbing tale that illustrates how a perfectly normal person can find himself caught in a web with no escape, forced to do the bidding of a monster until the most hellish of acts becomes normal.

Vargas didn't set out to make a cheap, exploitative scarefest riding high on the memory of a dark time in the city. Instead, he wanted to explore the deep nuances and gritty reality of a mass murderer and what made him that way. The result is a film that pulls no punches and echoes other dark gems like Kimberly Peirce's Boys Don't Cry.

How does someone stare into that time and carnage and manage to come out on the other side with a work of art? That's what we're going to look at in this week's cover story.