BTK Killer Horror: Cub Scouts Leader’s Vile Secret Exposed — 'It's Hard to Control Myself' (FPD CASE VAULT)

Dennis Rader was a devoted husband, doting father of two, Cub Scout leader and pillar of his church.

But behind this mask of normalcy raged a homicidal beast known as the BTK killer. The initials stood for Bind, Torture and Kill, signifying his sick murder method.

Over the course of three decades, Rader, a code enforcement officer in the Wichita, Kan., suburb of Park City, brutally murdered 10 people in a twisted bid to fulfill his crazed sexual fantasies.

Rader's demented murder spree began on Jan. 15, 1974, when he strangled Joseph and Julie Otero and two of their children in their home.

Lawmen were stunned to find the butcher hiding in plain sight, living in a modest ranch-style home. The place was eventually torn down as the community tried to erase the memory of the monster in their midst.

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He struck again and again, admitting in a letter to the local newspaper: "It's hard to control myself."

But he was finally busted in 2004 after cops traced one of his messages to a church computer he'd used.

Now 78, Rader is serving 10 life sentences at the El Dorado Correctional Facility in Kansas.