Facts that cannot be disputed....
Z-man stalked a kid
The kid didn't like being stalked
The kid kicked stalker's ass
The stalker didn't like having his ass kicked so he shot the kid.
If Z-man had minded his own damn business Martin would still be alive.
Those facts alone make Z-man responsible for Martin's death.
Except you can't kick someone's ass just or following you, but you can shoot someone's ass for kicking yours if you fear for your life