The issue is timing and proximity. The security guard saw (and recorded) the drivers of two cars behaving strangely in the hospital parking lot. This happened within minutes of the abduction AND within two blocks of the Smart home. What's more, the guard said when the cars departed, one went in the direction of the Smart home. The FBI reportedly has enhanced the video and got at least a partial license plate number for one of the cars. There was discussion of releasing it last week, but it didn't happen.
The most interesting aspect of this IMHO, is that the security guard was a former guard at the prison AND new Ricci well. That has to be an astronomical "coincidence". He handles himself well in interviews, seeming intelligent and articulate. My first question of him would be "why isn't he still a prison guard any longer", which probably has better benefits, retirement, etc. He doesn't appear old enough to be on a second career.