SIOUX FALLS, S.D. (KSFY) - Experts say it's not surprising that victims of Curtis Van Dam didn't immediately come forward with abuse allegations. It's often difficult for children to understand what's happening to them.
On Thursday, Sioux Center Police Chief Paul Adkins said he wasn't sure why so many victims waited to report Van Dam's abuse.
"I'm assuming they were scared, they were nervous," Adkins said.
Advocates said that is often one reason why, but there are also many others.
"For some kids they may think that's a normal part of that type of relationship," Michelle Markgraf, executive director at The Compass Center said.
And sometimes, a perpetrator is controlling the entire situation.
"Their perpetrator is threatening them and telling them to keep it a secret or threatening them to not tell," said Dr. Brooke Jones, a child abuse pediatrician at Sanford Health Child's Voice.
New documents reveal that some of Van Dam's victims were under the age of 12. Experts explained that can often make things even more complicated, because kids that age are going through puberty.
"Just because they do have a heightened sense of their body and about sexual things and it's difficult for them to talk about," Markgraf said.
There are signs parents and other adults can be on the look out for, especially if a child's personality or behavior suddenly changes. Jones said children acting sexually inappropriate, or using sexually inappropriate language for their age can often be one of those signs, but that's not all.
"They could have declining grades or they could revert back to a younger childhood age or activity," Jones said.
But sometimes, those signs aren't there.
"Just monitor and ask yourself, over the past three months, 'Is my child pretty much the same kid? Or is this child changing in how they approach life, in how their mood is?'" Markgraf said. "And if there's a change, it's worth asking that child what's going on."
The best thing any adult can do for a child who may be ready to tell you about his or her abuse...
"Recognize how hard it is for them to disclose that, be supportive and don't ask any suggestive questions, but be an active listener for them," Jones said.
Police said Thursday they were not releasing the exact number or victims or whether they were boys or girls at this time in order to protect the victims. That information is also not discernible from the affidavits.