Who cut off Crocodiles hand/how did he "lose" it

I've been thinking about things which are never really brought up about certain characters and i dont recall anything about Crocidiles hand being mentioned at all.

I've had an inkling that it was something to do with Ivankov or Dragon, maybe them being married and Crocodile cutting off his hand because something happened. Because we know that there is bad blood between Ivankov and him. Or maybe something boring happened like WB just cutting it off