You'd think that if DCYF was certain a child was being abused that they would rescue the child immediately. Apparently few children are being abused enough to merit that. Instead, DCYF waits until Friday afternoon, calls the kid's school, asks them to pull the kid from class for a pickup at school. Even then, DCYF has three business days to file an abuse petition, so there may be nothing to argue against. Ya gotta believe the children.
Kids are lousy liars.
They also don't keep secrets well. On the other hand, they are impressionable. Long interview sessions and leading questions will often lead to incredible stories of abuse. Older kids can stick to their story that abuse didn't happen, until an interview is made that has a transcript but the tape was lost. Even when there is a tape, it's worth checking the accuracy of the transcript.