How deep does the cover up go?

The evidence is mounting that the Oklahoma City bombing of the Alfred P. Murrah Building has connections to Islamic extremists that the government is ignoring or covering up. What is the possible reason that the government would not question a primary Middle-Eastern suspect that was identified being seen in the presence of Timothy McVeigh prior to the bombing?
The following is from the
Canadian Free Press:

"Evidence presented by Ms. Davis in her book and offered directly to the Congressman is so compelling that it could easily make a prima facia case for Middle Eastern involvement in the bombing. The evidence uncovered by Ms. Davis offers detailed witness accounts of a former Iraqi Republican Guardsman identified as Hussain Al-Hussaini being seen in the presence of Timothy McVeigh prior to the bombing, getting our of the bomb-laden Ryder truck the morning of April 19, and fleeing the Murrah Building in a vehicle identified and pursued by the FBI in an all-points-bulletin issued for Middle Eastern terrorists. More significantly, two federal court rulings establish that this Iraqi soldier has no provable alibi for the morning of the bombing. Overwhelming and fully substantiated evidence developed by Ms. Davis was deliberately sidestepped by the congressman as she predicted in an interview with the Northeast Intelligence Network almost a year ago."

"It is unconscionable to accept that the FBI never interviewed a primary Middle-Eastern suspect in the Oklahoma City bombing about the bombing itself, never issued an official on-the-record statement exonerating him of complicity in the Oklahoma City bombing, and despite the numerous questions surrounding the ties and activities of this individual, did nothing as he gained employment following April 19, 1995 but before September 11, 2001 at Boston-Logan airport – an airport where two of the 9/11 hijacked planes originated."