We rented it from BlockBusters back in 2011. It was a horror movie, in color, in English. The opening scene was a body in a garbage bag in the forest. The movie was about a red head young girl, a monster with claws and a very confusing plot line. At the end she killed her parents and it was reviled that she and the monster were one and the same.
The Big Bad (2011)?
http://www.imdb.com/title/tt1985219/?ref_=fn_al_tt_1
Sounds ALOT like the uninvited except for the part about the claws