OBAMA KILLS OSAMA (or so they say)....
I think we have a plausible explanation:
"Since Osama was killed seven years ago, this protoplasmic entity was clearly his zombie, hence the need to shoot him in the head.
Since you can never be too sure about zombies, best to dump the body in a deep ocean trench."
There you go, mystery solved!
(
On a more serious note... )