No, I think that a sub launched anti-aircraft missile is just one possibility. For all we know, the sub may have launched the DRONE missile that the other ships were supposed to shoot at.
Or, it could have been a missile fired from a small boat (like the one reported to have fled the scene right after the explosion of TWA800).
And what makes you think it's a sub launched anti-aircraft missile and not a surface-to-surface cruise missile? I won't even justify the drone part with an answer.
Or, it could have been a missile fired from a small boat (like the one reported to have fled the scene right after the explosion of TWA800).
That would shoot your whole subsurface to air missile theory right out the window wouldn't it?