Stephen Spielberg no longer allows one of his books to be published. Rage was found in a student's locker after he committed a violent crime. Being a responsible author he pulled the book. Do you think books (or movies) can cause kids to commit violent crimes?
History is full of young people committing violent acts but who never watched a movie, played a video game, nor read a book. I rather think that prescription drugs like antidepressants, or physical/emotional abuse are causes of violent the violent school crimes today.
However, where is parental involvement regarding movie ratings that have determined a movie or video came is inappropriate for kids?
I think it depends on the student. How impressionable is the child. If they see a violent crime committed on television and the act lingers in their minds in a bad way, I think the content of the movie is bad for the child. Personally, I do not allow my nieces and nephews to watch movies with violence in them because once the image is in their minds, I can't erase the image. Their ages range from 3 to 17.
The movie may give the student ideas about how to commit the violent crime in ways they never imagined. That is just my opinion.