(Should've known. But I must address the issue of the two girls...)
Grissom was reviewing the files, he suddenly got another call, "Greg? I thought I told you to get Warrick- what!?"
He was shocked. Brenda and Cassie were not in the interrogation room anymore.
Somewhere between Catherine getting attacked and taking her to the hospital, they dissapeared.
"Where was the cop? He was supposed to be guarding them!"
Greg explained that the cops were trying to detain the foster father, and he was only gone for a minute.
"Damn," Grissom felt his pulse rise. He just talked the Child Service agents to trust him and his CSIs and now the little girls were gone.
"Get Nick and Sara, and find the girls!"