i hate to say this and i hope im wrong but more than likely the remaining admin just moved all the coins to a wallet he controls so he can cash them out and move to some tropical beach somewhere in peace.
BTC-e had two owners. The first one was Alexander Vinnik, who is about to be deported to the United States, where he is going to spend the rest of his life behind bars. The second owner is another Russian guy called "Aleksey", who is in some country which is outside the US jurisdiction. He has taken control of all the coins and gone in to hiding. Now this may be a strategy to protect these coins from being confiscated by the authorities.
Or more like he is running off with the coins now that their criminal activities have come to an end.
I don't believe the US will confiscate bitcoins from anyone who hasn't committed any illegal act as that would be illegal on their part.