This, like many other attacks on America have been covered up by the F.B.I.
Look at the jet shoot down off Long Island. You gonna believe what the govt. tells you you saw or you gonna believe your lying eyes?
Why did the f.b.i. confiscate all relevant security videos around the Murrah building and refuse to release them to the public?
If it doesn't fit the company line the feds work hard to discredit it, even if it is correct.
There is a sort of an unwritten agreement between the leaders of both the Democratic and Republican Parties that neither party will penetrate too deeply into the other's secrets while that party is in office. Personal matters, like Clinton's promiscuity or Bush's National Guard record, may be fair game. However, issues like whether Clinton covered up possible radical Arab involvement in the Oklahoma City bombing will not be revealed in the lifetimes of most of us.
I agree, that TWA explosion just doesn't add up.
As in OKC, there are some things that don't add up, but I don't attribute the conspiracy to sinister govt. plots: I chalk it up to laziness, ineptitude, and cowardice.
If they (govt intel) look into these things, it means they might have to confront foreign govts, go to war, take action. Much simpler to avoid a thorough investigation.
So in a sense it is a coverup...of avoidance.
Regards
Probably for the same reason that they confiscated the videos from outside the Pentagon on 9/11.