And we do not know who initiated the scuffle that resulted in both men wrestling on the ground. Is it possible that Martin grabbed for or took the gun away from Zimmerman, which caused him to believe his life was in danger and that he had to use lethal force? This took place inside a gated community.
No we do not know. It could be that Zimmerman tried to grab the kid and the kid responded with knocking Zimmerman down and beating him. Or it could have been that the kid just attacked Zimmerman. Not enough evidence to convict so far.