Was 911 an inside job?

sounds reasonable for someone's opinion. but to be honest, who can actually tell us what had happened that day? no one will step forward for fear of getting killed or whatever it may be.. no matter how much we scrunitize this idea, there is no one who will uphold this in front of, say, Bush. Until he is out of office and someone else conducts a real, sophisticated and well-researched investigation, no one will know what had actually occured; whether it was an inside job or not.