(rsbm) (mho) (ahem, pardon me for attempting to be precise about this) (i am not a lawyer but dealt with data for 32 years in which precision was needed)
"an independent witness was very clear that his car was gone by the time of the incident."
I believe, personally, that this sentence greatly overstates what we know about that car. My own opinion would be that a witness CLAIMED to see the car gone by the time of the incident--subject to all the human errors possible. (see below)
"His car?" How do we know the car was his? Whose car was it? From everything I've read, we don't actually know who drove the car there, or who drove it away, or who owned it. We don't have agreement on what kind of car it was, much less if it was BG's car.
And as to the certainty of that witness's testimony, I quote:
from
Lessons From the Kennedy Assassination About Eyewitness Testimony | Texas Lawyer
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(re JFK Dallas murder): "Yet eyewitnesses to the assassination could not agree on even the most basic details of what happened in plain view in Dealey Plaza. These details include the number of shots fired, the direction from which shots came, and the number of assassins firing shots."
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No offense intended, honestly, but if I'm wrong about any of my criticisms, I'll cheerfully retract them, AND shine your shoes next time we meet. --ken