No one can supress the circumstantial evidence suggesting Nichols' ties to Abu Sayyaf.
That's true. But will anything ever be done with it? That's the question. I think the question of a conspiracy (other than the two actors, McVeigh and Nichols) can be substantiated very easily with the viewing of all the security video tapes collected.
I am among those that believe an interior blast occurred at least five seconds before the truck exploded. A careful viewing of the videos should show (in addition to the Ryder truck and its occupants) anomalous movement of the Murrah building relative to all the stationary objects in the pictures while the truck was still intact.
Maybe that's why we will never see the videos -- and that alone is justifiable suspicion for a conspiracy regardless of who was in the truck.