Sorry I'm just reading old transcripts to see what I might have missed. I never thought about what everyone did after they involved police, and after the bikes were found. I assumed they kept looking, calling the girls' friends, driving around town looking for them, etc.
Here is the transcript from the interview:
BROUSSEAU: OK. So then we watched the investigators put the crime scene tape up. They were down there for a very long time. I would say approximately three hours, maybe more, you know, doing their investigation.
http://transcripts.cnn.com/TRANSCRIPTS/1207/19/ng.01.html
So they just sat and watched? Did everyone or just part of the family? Surely at that point there was still hope that the girls were alive, why not look for them, why watch to see what police dug up?