Jon Gosselin is siding firmly with his son Collin in the family's bitter public fight. He now says his ex-wife Kate should be prosecuted over the abuse Collin claims he suffered as a child.

Jon pushes back on the mental illness claim

Kate has suggested Collin's accusations stem from mental illness. Jon is not having it.

"She needs to stop. He is not mentally ill," Jon said in a TV interview. "I would definitely have grounds to sue Kate for defamation and libel. I don't even think it's suing. I think it's just criminal charges. So, that's up to the state."

He also flipped the situation around. "Let's put the shoe on the other foot. What if I did these so-called things? Where would I be sitting right now? I'd be sitting in a jumpsuit and we would be doing a live feed."

What Collin says happened

Collin has said he passed several psych evaluations and that his mother is the one who needs one. His allegations are disturbing. He says Kate zip-tied his hands and feet and locked him in a room, among other claims.

Collin says child welfare workers looked into his case and took note of bruises on his body. The agency closed its probe and labeled the allegations "unfounded" in its final report.

Jon wants the truth out

Jon and Collin were out together in New York City on Thursday. Jon said all he wants is for Kate to be honest about what went on in their home.

He has a Netflix documentary on the way and sees it as his chance to share his side. He wants Kate to share hers too.

Collin is also reaching out to his siblings. He is asking them to look into things for themselves. He says he has receipts showing their mom took money from them.

Kate has dismissed the accusations.