Forget about those hungry lawyers ar Rosen. They are waiting on the auditors to feed them with the evidence and they are basically doing nothing.
If you want to seriously pursue a legal case assuming YU stole the money, the best bet is to launch a lawsuit in China against YU, Sabrina, GUO and all the directors. In addition to a very low legal cost in China, the sentencing would be harsher to up to EXECUTION if found guilty. Contrary to many opinions out there, Chinese legal system do work. I have seen billionanires sentenced to death in China & executed.