In a video posted on a website by Zimmerman's defense team, Zimmerman said Martin saw his gun and reached for it as the two scuffled on the sidewalk at a gated apartment community in Sanford. That's when Zimmerman said he pulled the gun and shot the teenager.
The tape shows two butterfly bandages on the back of Zimmerman's head and another on his nose. There are red marks on the front of his head.
On the tape, Zimmerman did a reenactment of the scuffle with Martin in the moments before he shot the 17-year-old from Miami. Zimmerman said Martin kept "slamming and slamming" his head on the sidewalk. "It felt like my head was going to explode," he said.
Zimmerman told police the confrontation began when he saw Martin walking toward him on the evening of Feb. 26.
Zimmerman had already called 911 after spotting the teen in the neighborhood. Police say Martin was staying at his father's girlfriend's townhome in the Retreat at Twin Lakes, a gated community in Sanford. The teen was walking back to the home after going to a nearby convenience store.
Martin was reported missing by his father, Tracy Martin, the next morning.
The Orlando Sentinel (http://bit.ly/M8ARMg) reported that Tracy Martin called 911 the morning after the teen's shooting and said he had been missing since the night before. During the 3-minute call, he gave the dispatcher identifying information about his son. A few minutes later, the dispatcher called back to get more information about the teen and told Martin an officer was on his way for an interview.
Officials released a transcript of the 911 call Wednesday.
Also Wednesday, Sanford City Manager Norton Bonaparte fired police chief Bill Lee, who had been criticized for his department's initial investigation into the shooting.
Zimmerman has been charged with second-degree murder in the shooting. He claims he shot the teen in self-defense, under Florida's "stand your ground" law.