Colin Gosselin, one of the sextuplets showcased along with their twin siblings on reality TV throughout their childhood, claims in a new memoir that, behind the scenes, mom Kate locked him in the basement for two years, monitored him with cameras, restrained him with zip ties and then sent him to an abusive institution.

The sextuplets had just turned 5 when their parents divorced, and their older twin siblings were 9. Today they are 22 and 25. The divorce came three years into the 10-year run of TLC’s “Jon & Kate Plus Eight,” which was then renamed “Kate Plus Eight.”

The worst of it started when Collin was 9, the 22-year-old recounted in a memoir released Tuesday, “In the Shadow of Eight: Surviving the Reality of My Childhood,” revealing details of alleged abuse he has spoken about previously. That’s when Kate told him his father, Jon Gosselin, no longer wanted to see him, People reported, based on an advance copy. She also moved him out of the finished basement room he’d shared with brothers Aaden and Joel and into the unfinished part, where he slept on an air mattress next to the cleaning supplies. When he didn’t perform for the cameras as she wanted, Kate would yank him around by the earlobe and slap him, he claims.

When his swollen earlobe caught a teacher’s attention, Collin spoke to him and a guidance counselor, which his mom “was not very happy” about, he told “Good Morning America” on Monday. During fourth grade, she pulled him out of school. She told the public Collin had special needs. But it was really because “I threatened my mom’s income” and image, he told “GMA.”

Collin Gosselin of ‘Jon & Kate Plus 8’ alleges childhood abuse in memoir
From “Jon + Kate Plus 8,” Kate Gosselin and her children attend the Discovery Upfront event at Jazz at Lincoln Center on April 23, 2008 in New York City. (Photo by Amy Sussman/Getty Images for Discovery)

The question of child exploitation had been raised occasionally as the series went along, but that apparently did not trigger a closer look. Now, as the children of reality stars emerge as adults and speak out, some of the effects of their loss of both agency and privacy while growing up are becoming evident.

Collin Gosselin was pegged by his mother on the show as having “special needs” and placed in an institution that was “helping him learn the skills he needs to be the best him he can be,” she told People in 2016. But in his memoir, Collin calls it a hotbed of abuse and claims he was so branded because he pushed back on filming. The facility, Fairmount Behavioral Health System, said in a line included in the memoir that it doesn’t comment on specific residents but does provide “individualized treatment” based on a patient’s particular needs.

“People from that time would probably say I was a ‘difficult kid,’ I won’t argue with them,” Collin wrote. “I probably was. At this point, my rebellion had evolved to become more than just a quiet resistance. I didn’t always know how to express what I was feeling, so it came out sideways. I started to talk back, throw tantrums, melt down the way kids do.”

When he left Fairhaven at age 14 he moved in with his father, who fought to get custody of him and is now his “best friend,” Collin told E! News recently. Sister Hannah also lives with them. The other kids don’t speak to their father. Kate had not addressed the memoir specifically on Tuesday but has said she never intentionally harmed her children and that anything she did was under professional advice.