Zero's idea is a good one to build on, I think. Maybe you could script it out where the child is viewing a scene of Jason killing somone, and keep panning back and forth from that to the murder. That way he makes a connection between his dad & Jason. This sets it up that, in a sick way, he idolizes what his dad is doing: being just like his favorite icon on the big screen.
Also, you're dialogue does sound a tad scripted, maybe a little soap opera-ish. I'll offer some clean up suggestions after a bit, if you'd like.
__________________
|