I don’t understand how Corey can overcome her burden if Zimmerman lost Martin, and then Martin initiated the confrontation as the evidence seems to indicate.
Maybe she’s counting on the jury being too scared to acquit. I hope not, but...
As for evidence, as far as well know, the only witness to the first punch is Zimmerman (unless there are others who saw it that first night or who have manufactured their account since then). The witnesses don't have to believe him. The statement that Martin's girlfriend attributes to him could have been made when Zimmerman came upon Martin. What's a jury (whose names and addresses may be public) going to decide? And we don't know what else Zimmerman told the police during the hours of interrogation at the station that night.
I think Corey has a tough burden, but she has the power and money of the State of Florida on her side, the sentimental story for some, public fear of reprisal if Zimmerman is found not guilty, witnesses who appear to have changed their stories to favor Martin since the night of the encounter, witnesses who seem to have appeared since the first night, advocates wanting to make their bones testifying as experts against Zimmerman . . .
And Zimmerman has a TV News expert as an attorney, limited financial resources, and a jury that's likely already heard false evidence in the news. You can't unring a bell.