What is the name of this movie?

I saw this movie on cable in 2007 so it probably came out a few years before it...but it was really good. I don't know the name of it. It was about a family with the dad as an undercover cop, and the child runs away and gets abducted by this couple and they take him to their apartment attempting to molest him, but he hides in the bathroom and calls his neighbor who comes. When she knocks on the door the couple is really nice and everything seems normal and they seem like a nice family...they even have two children who are sleeping in bed. Then the neighbor leaves but comes back when she realizes that the couple didn't have any pictures of their children...which is suspiciously odd. She then barges into the living room and opens up the closet and finds many many cabinets of all these creepy serial killer tools and and lots of drawers with names of children on them. And then she looks all over the house and eventually finds the kid hidden somewhere with a plastic bag over his head tied up. He is basically dead but she performs cpr and saves him. She points the gun at them, and they try to bribe her with money, but she instead calls the police saying she is in a room across the hall and heard two gunshots. She immediately shoots both of them and leaves, taking the boy and the two children with her. Epic. So ya what was the name of the movie?