In 2003, four people mysteriously disappeared. Their paths never crossed, but they were all connected in one monster's web of darkness, deception, and lies. That monster's name was Scott Kimball. For years, Kimball led a double life. By day, he was a paid FBI informant. But by night, he was a cold-blooded serial killer.

Retired FBI Special Agent Jonny Grusing provides firsthand insights into his high-stakes investigation into one of Colorado's most chilling serial killer cases, as detailed in his book, The Devil I Knew.

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