George Zimmerman called police, and started "walking in the same general direction to see where the individual was going," and get an address for police.
At one point, he said, Trayvon approached him saying, 'Do you have an f-ing problem?' George replied no and reached for his cellphone.
Trayvon "punched him in the nose, his nose was broken, and he was knocked to the concrete." Robert Zimmerman said. "It's my understanding Trayvon Martin got on top of him and just started beating him in the face, in his nose, hitting his head on the concrete."
"After nearly a minute of being beaten," Robert Zimmerman said George tried -- with Trayvon still on top of him -- to move away from the concrete onto the grass. In doing so, the gun he kept in a holster on his waist was exposed.
"Trayvon Martin said something to the effect of 'you're going to die now' or you're gonna die tonight' -- something to that effect," he said. "He continued to beat George. At some point, George pulled his pistol and did what he did."