ClayCat,
If he was there to deal drugs, I would think he lives locally.
From what I've read of your visit to the bridge, and the pictures I've seen, this is not a place that just anyone could find.
Since he had a 'meeting' there, he would have to be familiar with the area.
So, now the killer(s) know that someone can identify them.
If he wasn't part of the shootings, I think he's gone, he running, and not from the police. The police are probably the least of his worries right now.
But what really amazes me, is that someone else knows this guy in the truck.
There are others who might have had dealings with him, are his neighbors, work with him??
Seems to me that somebody knows more than has been told. Someone can identify the POI. Perhaps he's not a suspect, but LE just wants to interview him. I would hope that someone would call LE and give them this info, even if they don't reveal their identity....