The scenario you describe with your question is correct in every detail. For this important mission, an interdimensional portal of extraterrestrial origin was placed in this building on the 6th floor. This was done so the shooters could come in, physically, after the floor had been cleared of other workers—that was seen to via mind control. And then after the shooting at the President's motorcade was carried out, they left a rifle behind but exited through the portal and were taken, energetically, to a hovering spacecraft for their departure. This completely prevented any possibility of being seen, or detained at the crime scene, but rather ensured a safe getaway after the assassination. The inability of the Warren Commission to explain Oswald's movements prior to being found having lunch in the building lunchroom, within a minute or two after the shots were fired, was perplexing for them and, without their coverup, represents an important clue as to the nature of how the assassination was carried out, as a number of aspects cannot be explained through conventional perspectives.
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