I'm not sure what you mean by conspiracy theories--the possible missile strike or the alleged cover-up, but virtually every terrorist strike that occurs is a conspiracy. The 9/11 incident was a conspiracy. The first WTC bombing was a conspiracy. The government typically charges terrorists with conspiracy along with other things when they're caught. Terrorist strikes by nature must be carried out through the coordinated action of numerous individuals--a conspiracy by definition.
Now, it is much harder to envision our own government officials being involved in a conspiracy, but it isn't impossible. Implausible but not impossible. That may be what you're saying.