if you know the law why in the hell are you still asking questions ? It's legal to be armed and it's legal to "follow". Z is charged with 2nd class murder--why not just go straight there ?
I don't think he showed malice.
But I think he showed criminal negligence.
Web definitions
(law) recklessly acting without reasonable caution and putting another person at risk of injury or death (or failing to do something...
wordnetweb.princeton.edu/perl/webwn
I think following him the first time, then not returning to his truck the second time was a reckless move and was acting without reasonable caution.
As Martin, all he would have had to do was prove he felt reasonable fear for his life or bodily farm. Which would have been very easy, even more so now.... Since he is dead. He had good reason to be fearful.
In other words he didnt have to retreat.
And Zimmerman's reckless actions caused his death. I hope his patents also sue him.