And there is a witness who said GZ continued to follow, and even chased TM.
DE LA RIONDA: Isn’t it true, sir, that at least one witness described a person chasing another person in the back of that area where that murder occurred?
GILBREATH: Yes.
...
O’MARA: A couple of questions...The continued to follow that Mr. Zimmerman continued to follow
what evidence do you have to support that?
GILBREATH: He was told not to follow him, he continued on for a period of time.
O’MARA: How long?
GILBREATH: I don't know … I would say less than a minute before he hung up, which is prior to the encounter between the two,
O’MARA: Okay. Any other evidence besides that there was a phone call that he was on for a minute? Any other evidence, any other witnesses?
GILBREATH: To?
O’MARA: To the fact that he quote continued to follow.
GILBREATH: We have a witness statement who observed, that was on the perimeter of this, who observed shadows or figures, excuse me, running by her residence.
O’MARA: Do you know which way or who they were, or anything?
GILBREATH: They...I cannot identify who they were, but it was at the same time frame this occurred.
O’MARA: Ok. Besides that - any other evidence to support your conclusion that Mr. Zimmerman continued to follow?
GILBREATH: Other than his call and that witness?
O’MARA: Yes.
GILBREATH: And the fact that where it ended up. No.
O’MARA: Well you do have some other evidence don’t you? We had Zimmerman’s statement, don’t you?
GILBREATH: We have Mr. Zimmerman’s statements, we have the shell casings and we had Mr. Martin’s body at the scene.
http://www.wral.com/news/video/11004815/#/vid11004815