Kyron Horman's Parents Speak Out

The parents of missing 7-year-old Kyron Horman are speaking out about his step-mom who was reportedly the last person to see the boy before he disappeared.  INSIDE EDITION has the latest.

Kyron Horman's mom can't hide her disgust for the step-mom at the center of the case.

"I've known her a long time.  I know she's lying," said Kyron's mom, Desiree Young.

She says she thought Terri Horman was involved in her 7-year-old son's disappearance the moment he went missing.

"I thought she better not have done anything to my son," said Young.

She and ex-husband Kaine Horman both appeared on Good Morning America, and he also believes that his bodybuilding second wife has been lying from day one.

"There was just certain details that didn't make any sense to me and gave me that sick to my stomach feeling," said Young.

They say they both easily passed lie-detector tests police gave them, but Kyron's step-mom behaved strangely during the tests.

Kaine Horman said, "She went in and went through part of it, and walked out in the middle of it.  And then delayed, for well over a week, before the second one.  Huge concern."

The father's handwritten petition to a Judge for a restraining order against his wife has now been made public.  He writes, "I believe respondent (referring to Terri) is involved in the disappearance of my son Kyron. I also recently learned that respondent attempted to hire someone to murder me."

Kyron's parents say they can only hope that if Terri Horman was involved, she had help, and that someone out there is caring for their shy little boy.