"He was barely conscious. The last thing he remembers doing was moving his head from the concrete to the grass so that if he was banged one more time, he wouldn't be wearing diapers for the rest of his life and being spoon fed by his brother," he said. "There would have been George dead if he hadn't acted decisively."
A police report notes George Zimmerman had blood on his nose and the back of his head. But in a surveillance video, obtained exclusively by ABC News, shows Zimmerman from inside the Sanford police department just after the shooting. Zimmerman's shirt and jacket appear unstained and there is no visible sign of blood on his face.
Zimmerman, a neighborhood watch volunteer, claimed self-defense the night he fatally shot Trayvon Martin. Zimmerman's attorney maintains his client's nose was broken fighting with Martin, and his head was slammed to the ground several times.
While cautioning that the video is grainy and far from conclusive, some legal experts agreed it does raise questions about Zimmerman's story. The video was made about a half-hour after the shooting Feb. 26.
Zimmerman has not been arrested, despite demands from black leaders and others that he be charged with murder or manslaughter. But a special prosecutor appointed by the governor is investigating, along with state and federal authorities.
Also in dispute from that night is exactly who was heard screaming on the 911 calls moments before Zimmerman fired his gun.
"He was screaming out so many times, I know that voice. It sounds just like my voice," Robert Zimmerman said. "He's been diagnosed with PTSD. He was not right from the moment it happened."
Martin's girlfriend, who was on the phone with him minutes before he was shot, told ABC News that Martin said he was being followed.
"When he saw the man behind him again he said this man is going to do something to him. And then he said this man is still behind him and I said, 'Run,'" said the 16-year-old girl, who is only being identified as "DeeDee."
The girlfriend said she heard a man asking Martin what he was doing there. She heard someone being pushed to the grass and then the call ended.
The protest over Martin's death has reached Capitol Hill. On the House floor Wednesday, Ill. Congressman Bobby Rush took off his suit jacket to reveal a hooded sweater, which was what Martin was wearing the night he was shot.
"Racial profiling has to stop, Mr. Speaker. Just because someone wears a hoodie, does not make them a hoodlum," said Rush.
The Democrat was interrupted by the presiding officer for violating rules on wearing hats in the chamber. Rush was then escorted off the House floor. Several African American lawmakers have called for Zimmerman's arrest.
ABC News and AP contributed to this report.