Can someone help me figure out what this movie is called? Please & thank you. (:?

Okay, Saturday night i was watching a movie. The start showed a little girl named Julie, or Julia in an enclosure. Cement starts pouring out of the wall, & she dies. Apparently there are 16 murders in this building, and a girl named Sam is hired to demolish it. Sam has no idea that these murders happen, until a boy named Jimmy tells her. Jimmy turns out to be insane, sacrificing his own dog, & kidnapping Sam. I missed the end of the movie, & would really really like to see it, but i have no idea what the tittle is. In the movie, it also has a guy named Mendoza(i think) in it. So, could some one please tell me what this movie is called? Thanks<3(: