The drag mark was apparently a scuff on the door sill so you would even have a hard time deciding whether it was going in or out of the car. Especially from a photo.
--------there was also some blood on the passenger door sill which the expert felt showed direction into the car.
But one could read his testimony as combining his view of the photographs with the assumption that a body had been in the car therefore it had to have been dragged in. And he testified that he could not see any clear evidence of the "large bloody object" being "dragged back out"
As you say snively "especially from a photo".
Who knows what evidence he would have been able to conclude had he examined the car personally.
Somebody obviously wiped the car down as well, so it seems fair they noticed a blood mark on plastic or the back of a seat and wiped that off but missed a dirt scuff on a plastic door sill.
-------- I don't see it as "obvious" that somebody wiped down the car. Absolutely possible, but there were several prints inside the vehicle but they were smudged or overlapped too much, (not sure if that's the right description).
Fwiw:
The one CFS identification guy that testified was a work of art. He took the gear shift knob off and carried it resting on his forefinger and middle finger to the glue box for fingerprinting. The only prints on the knob were HIS OWN. Which means he never wore gloves.
There was also a barrette under the driver's seat that was in a photograph in evidence, and the defense lawyer asked about it and this CFS guy says oh he didn't have it on his items list from the car and it must have gotten lost somewhere because he didn't have a record of it.
If the family was part of the disappearance they could have just left the car near any major transportation hub and the assumption would be she just ran away. No, the car left at the body shop was because somebody needed something to transport a body right away and come back to get their car. If the family was involved why would they want to make it look like a murder which would be investigated. Just park the car somewhere around the subway line or something and the assumption would be she just took off and left and bought a train ticket out of town.
----------- I agree that if the family was involved that planting of the blood doesn't really make sense because it brings immediate attention to foul play and a good set of Detectives would start with the family to eliminate them.
Which didn't happen in this case but the family wouldn't have known that.
------- having said that, the scene does not exclude one family member from arguing and accidentally killing EB.
This individual may have panicked and covered it up the best he could that night.
Any other family members that may have suspected something like this happened may not have wanted to specifically know the details but did whatever they could to protect this person and forward any help to LE in putting RB away for the crime.
The police would hardly look at something like that because she was an adult.