The initial event was not the explosion of the center fuel tank; another impact affected the airframe prior to that explosion.
Missiles do not require "warheads" to alter airworthiness.
There are bombs which do not leave chemical particulates to be traced among shards of metal; nor do they have fuzes.
The federal government lied about the presence of U.S. military operations and ships in the area.
There are many kinds of missiles other than "shoulder-fired."
There are many, many locations from which a missile could have been fired.
Not a good idea to discuss more ... which would reveal more.
If the federal government says what really happened, then some secrets more valuable, 'tis their thinking, will be compromised; and they would prefer to not do that.
The exclamation that "so many people could not keep a secret(!)," is sometimes true and sometimes false.
In this case, as well as the Murrah Building, I think the reason was Clinton's unwillingness to confront Arab terrorists, and risk alienating them, for his on personal political purposes. Therefore, they didn't exist.
Whatever happened to the confident and determined FBI agent in charge who we saw on tv for the first two or three days assurring us that the case was about to be solved and the perps brought to justice? He disappeared like an apparition.