Those were on the computer at the mothers house, not the house in CC. Toombs was full of BS. He was trying to fabricate a child porn case against SA because he did not have evidence in HD's disappearance that supported his pet theory. In the end that attempt came to nothing as well, since there was no evidence that SA had child porn either. That was a consistent theme in the entire investigation, they clutched at the thinnest straws trying to find evidence to support their "gut feeling" of what happened rather than follow the evidence and go where it led them (which was the professional thing they should have done). Toombs's lack of objectivity and obstinacy is the primary reason IMO why this case will never be resolved. The porn found at CC was much less than 100k images, just a few videos on his phone and a CD IIRC.