esniper

Didn't you see the Academy Award, they repeated said that  it's a copy of HK movies by Andie Lau. Even Martin Scorses thanked him in his speech. It's an exact copy of Infernal Affairs, although the HK version goes upto 3 series.

http://en.wikipedia.org/wiki/Infernal_Affairs

http://www.miramax.com/infernalaffairs/

http://www.lovehkfilm.com/reviews_2/infernal_affairs.htm