One of the things I find most interesting about this case is the demonstration of witness fallibility. Bodycam video shows Roddie talking about what happened. He says repeatedly and confidently that when Arbery ran past the truck, Greg got out of the truck and was in front and was pointing his pistol at Arbery. When questioned about the details, he said he wasn't sure if he saw Greg get out of the truck or exactly what he did, but he did know that he saw Greg in front of the truck and saw him pointing his pistol at Arbery.
That didn't happen. We have video that shows that Greg was in the back of the truck the whole time. There is no reason for Roddie to lie about that. It is very strange that he had that false memory.
It isn't - our memories are - to sum it up as simply as possible - crap. That is why the gold standard is to take witness statements immediately and before the witness has had time to talk to other people by someone who is trained to not prompt a witness (albeit the interviewer is often unknowingly prompting). Even then precaution needs to be built into the investigative process to not overly rely on witness statements to direct an investigation.