By the way, there are constant references in the press in recent days of how Hezbollah was responsible for the killing of US marines in Lebanon in 1982. To the best of my knowledge this was never proved.

According to Caspar Weinberger who was Secretary of Defense in the Reagan administration from 1981 to 1987, in a 2001 interview:

But we still do not have the actual knowledge of who did the bombing of the Marine barracks at the Beirut Airport, and we certainly didn't then.