Jordan Bleimeyer was 5 years old and weighed just 29 lbs. when he was rescued from a life of captivity in the spring of 2014.

TELL DR. PHIL YOUR STORY: Huge family drama?

His father, Bradley, was sentenced to 15 years behind bars and his stepmother, Tammi, is currently serving a 28-year sentence for injury to a child by omission. The couple was accused of starving and abusing Jordan, along with keeping him isolated in a small cubby located inside a closet underneath a staircase at their home.

WATCH: Stepmother Who Denied Abusing Her Husband’s Child Gets 28 Years Behind Bars

Five years after Dr. Phil originally brought Jordan's story to the airwaves, three of his step siblings, Cody, Allison, and Dylan are speaking out for the first time about what they saw and heard in the home.

“I heard screaming,” says Dylan, describing an occasion when he says he heard Brad go into the room where Jordan was kept, followed by the sound of a taser going off.

“Brad was definitely the main abuser,” claims Cody, who is credited with alerting authorities to the abuse. He claims Tammi would sometimes question her husband about what he was doing to Jordan, “But she kind of stopped. She said it wasn’t her kid and she didn’t have a say in it.”

WATCH  A Dr. Phil Exclusive: The Boy under the Stairs?

What else do Tammi Bleimeyer’s children have to say about what went on inside their home; and if, as they claim, Bradley was Jordan’s “main” abuser, why did they testified against their own mother in court?

Check here to find out where you can watch this Dr. Phil exclusive airing Thursday.

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Teen Says She Brought Bread To Her Stepbrother When Their Parents Starved Him