Interesting post from the spacex subreddit. It looks like we might get to see a recording of the first stage return (if it works).
http://www.reddit.com/r/spacex/comments/1nd0qc/american_isla...
http://www.reddit.com/r/spacex/comments/1nd0qc/american_isla...
http://www.marinetraffic.com/ais/default.aspx?mmsi=367035570...
It'll be interesting to find out what happened, if SpaceX tells us. It could be anything from a breakup at hypersonic velocities to the stage sinking after dropping from three feet over the water. (Or maybe they were just there to observe that a destruct charge went off?)