Jurisdiction of the USA in high seas mutiny?

I do not think there is a Great Debate here, just a factual question about international law, so I post in GQ.

A crewman kills the captain and the mate on a foreign-registered vessel on the high seas. No American citizen or interests are involved and yet the Coast Guard seize the ship in international waters and bring the man to trial in the US. Can someone explain the legality of all this? Why and how does the USA have jurisdiction? Furthermore, why would the US want to get involved? Why not send the whole matter back to China or Taiwan?

I would also comment that killing people is not nice but it seems the man was held in what pretty much amounted to slavery. Remember the Amistad?

Washington Times
CNN (Google’s Cache)