Guns don't kill people ....

[sexobon]

In addition to the charges brought against the boy, the boy's mother would seem to be culpable of reckless endangerment for not securing the firearm (there's nothing about the boy trespassing in the mother's home to get it). The firearm can be configured for safe carry in the backpack even under the conditions of the pack being slammed down; so, it was a matter of human negligence that the firearm was either left "cocked and with the safety off" by the mother; or, configured that way by the boy. That was neither a safe configuration for firearm storage nor any manner of carry. The safety should not be off until one is ready to pull the trigger. For backpack carry, there shouldn't have been a round in the chamber either.

The boy claimed he was going to run away. A similar situation could have developed if his mother had recklessly left her car keys in her car and the boy got in and drove away then hit someone because he didn't know how to properly control the vehicle.