If you look at the map, there are zero flock cameras reported in that region.
None in Moscow Idaho where the murder happened, none in Pullman where he lived, and none showed between the locations.
So I'm not overly surprised by this.
At what point do we accept that all systems are flawed? There could be many variables as to why the perp wasn't in the car. Maybe the perp stole the car. Maybe the perp borrowed the car. Maybe these systems do not work well in fog etc etc. I don't know how we're supposed to advance technology that makes us safer without getting into these muky situations from time to time.