I strongly urge you to not view your child's behavior as anything other than fear-based. This child's life has been turned upside down. AGAIN. Imagine how it would feel if you were in a similar situation--taken from the home you knew (no matter how bad it seemed to be to you). AGAIN.
Here's a resource that I'll hope you'll take a look at:
Heather T. Forbes, LCSW
Good luck!