Young couple goes on van tour of US, boy comes back with van - no girl

I have so many questions about this case, and I doubt most, if any, will be answered ultimately. Most of them center around the timeline and actions of both Brian and his parents. Another is how did Mr Laundrie know where to look for Brian? According to the segment I saw on NBC this morning, he is the one that found the backpack, picked it up and carried it to a police officer...sounds wonky. When they found the car parked there, why weren't the dogs able to follow a scent from it to where he was? Why were the Laundries allowed to move the vehicle back to their home before confiscating it? If LE didn't know about the vehicle until after the Laundries brought it home, more questions....why did they bring it home? They didn't think Brian would return and need it? Still more questions on my mind that I would like the answer to because a lot of these unanswered questions point to the parents helping him run and hide.