its a thai or korean or may be a japanese movie its about 2 girls or it might have been boys they were sisters or brothers and its start like the movie bedevilled  they were young children and they lived in a home that were really poor and the father i beat them up many times.  they went out to party and something there went wrong a murder or something or just a fight between them and 1 of them did run away to hide and that was 1980 or 1990 so the movie continue after that they have been growing up. one of them change identity to a guy or a she dont remember just because do get closer so someone for revenge.  the movie is all about revenge and at the ending of the film the cop find out that he really was a she or he . and a litle bit later they were sitting on the roof top together. think the movie was made 2002-2007