I saw this documentary a few years ago (or at least, one similar to it).
Horrifying story, yet fascinating also - what do they call it, car-crash tv ?
I've dived with sharks a few times, for the most part they aren't too interested. My worst experience was with a lone Barracuda - who took far too much of an interest in me for my liking and followed me for about twenty minutes. Fortunately, I found the boat before he decided he was hungry!