Any conspiricy theorys about 9-11?

Im doing my reasearch and I am wondering about people who wittnesed 9-11 and their deaths... did the C.I.A. kill them? yes or no and why??? Where their bombs in the twin towers??? How did Berry Jennings die??? Does ex president George W. Bush have anything to do with 9-11? Who killed the Bushes baby sitter???? Please answer wisley.