"Trayvon Martin said something to the effect of, 'You're going to die now' or 'You're going to die tonight,' something to that effect," Robert Zimmerman told Orlando TV station WOFL. "He continued to beat George. At some point, George pulled his pistol. Did what he did."
A surveillance video from the Sanford police headquarters the night of the incident raises questions about the description of a beating.
It shows Zimmerman, his hands cuffed, exiting a patrol car and being led into the police station. First broadcast Wednesday by ABCNews.com, the video does not provide close-ups, but also does not show clear signs of Zimmerman having injuries.
Joe Oliver, a friend of Zimmerman's, said Zimmerman told him he was "cleaned up by cops at the scene" that night before being brought to the station.
Oliver also said it was discovered the next day that Zimmerman's nose was broken.
Craig Sonner, legal adviser to George Zimmerman, said Thursday the video does not support or contradict Robert Zimmerman's description. It is "very grainy," he told NBC's "Today" show. Sonner also noted that the injuries Zimmerman sustained were "later cleaned up."
A police report says Zimmerman was bleeding from the nose and back of his head when police arrived at the scene of the killing February 26. He was given first aid in the police car, the report says.
Sonner noted that in the video, at one point an officer appears to be looking at the back of Zimmerman's head.
While more details in the case surface, Sonner said, "I'm not going to litigate this case in the media."
Zimmerman has not been charged.
When asked whether Zimmerman is able to leave his home, given the death threats he has received, Oliver said no.
Martin's death has sparked outrage and protests across the United States, moved President Barack Obama to call it a tragedy, and prompted a federal investigation.
Zimmerman's father vehemently defended the shooting in the interview with WOFL, but asked that his face be obscured because he says he fears for his safety.
Robert Zimmerman told the news station that Martin confronted his son first and pummeled his son continually.
"He was punched in the nose. His nose was broken," Robert Zimmerman said. "He was knocked to the concrete. Trayvon Martin got on top of him and just started beating him. In the face. In his nose, hitting his head on the concrete."
Robert Zimmerman was not there the night of the shooting and did not say how he knew the details of the altercation.
The elder Zimmerman's account was disputed by Martin's family attorney and several legal experts who looked at the video.
"The injuries that made it sound as though he really should have been on a stretcher are not apparent in this tape at all," said Marcia Clark, the former prosecutor in the O.J. Simpson trial. "He moves freely. He moves fluidly, not like someone who has just been through a beating in any way, shape or form, someone whose head has been pounded on the pavement as hard as described, someone whose nose was broken and bleeding. That tells you a great deal."
Sybrina Fulton, Martin's mother, said the video is another strong piece of evidence proving her son was killed unjustly.