The hacker just returned 12 1/3 Million additional NXT to BTER.

+ 6 Mil
...

+ 10 Mil

Which about solves it.

That's good news, how many Nxt does the hacker still have left to return?

about 8M

well, he said he believes in NXT, so he probably won't return it.

He should return the stolen Nxt and buy Nxt from his ransom BTC. That would be more appropriate imo.