So shoot him. it's not much of a stretch to think Zimmerman knew he was dealing because he also Facebook stalking him.
No, you shoot him after he attacks you, slams your head into the ground, then tells you: "you're gonna die tonight [redacted]."
If someone where to say that to you, I would want you to have the legal right to shoot them, as long as you didn't initiate the altercation.
I don't believe TZ initiated the confrontation, I believe he was only guilty of following him (which isn't a crime) because he suspected him of breaking into houses. It really doesn't matter why he had those suspicions; if he were incorrect in those beliefs, TM probably wouldn't have jumped him and he would have said: "eff off, my house is right there." And the whole thing probably would have ended there.