potentially better ending....
Kale goes to the house and finds his mother dead of a slit throat showing Turner already killed her. Kale races up to the door and Ronnie meets him there, but Ronnie is stabbed in the back by Turner and dies. Kale and Turner fight for a while, and the police (responding to Gueterriz's call) arrive on the scene. Kale gains the upper hand and is about to stab Turner with the shears when Turner flips the garage door up, and the police (upon seeing Kale armed) gun him down on the spot. Ashley is horrified, but sedated by the paramedics on the scene. Turner tells the cops Kale killed all the people and went crazy. Ashley tries to say different, but the doctors believe she is hysterical and take her away.
7 months later, in a new town, a boy is watching out the window and sees a man mowing his lawn,. The man stops and looks up, revealing Turner who grins.