The elder Zimmerman spoke, on camera but without showing his face, to Orlando, Fla., TV station WOFL, to share his son's side of the national story.
He claims Trayvon Martin attacked first and may have killed Zimmerman.
"It's my understanding that Trayvon Martin got on top of him and just started beating him," Robert Zimmerman told WOFL. "Martin said something to the effect of, 'You're going to die now' or 'You're going to die tonight.'"
"He continued to beat George. At some point, George pulled his pistol ... and what he did."
"He was punched in the nose. His nose was broken," Robert Zimmerman insists. "He was knocked to the concrete. Trayvon Martin got on top of him and started beating him."
"Beating him in the face. In his nose, hitting his head on the concrete."
The comments came just after the George Zimmerman surveillance video, taken at police headquarters the night of Martin's killing, was released.His hands cuffed, Zimmerman does not appear to have substantial injuries, though the video does not show a close-up of the neighborhood watchman.
The video was taken four hours after the incident took place.
"The injuries that made it sound as though he really should have been on a stretcher are not apparent in this tape at all," CNN analyst Marcia Clark said.
"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."
Zimmerman's attorney Craig Sonner described the video as "very grainy" on NBC's Today, noting that Zimmerman had been "cleaned-up" and received first aid care in the hours between the incident and his arrival at the police station.