The Cognitive Interview helps people remember details. Child interviewing helps children feel safe and...

The Cognitive Interview helps people remember details. Child interviewing helps children feel safe and answer questions. Both help investigators get facts without perssue.
First, I would talk to the parent and explain why the child's help is important. Then, I would ask the child simple questions and let them talk. I would not pressure the child or tell them what to say.
Body language should not be used to decide if someone is lying. Honest people can be nervous too. Investigators should check facts and evidence instead of judging how someone acts.