George Zimmerman's father claims Trayvon Martin beat his son, threatened his life

In the moments before Florida neighborhood watch volunteer George Zimmerman fatally shot 17-year-old unarmed black teenager Trayvon Martin, the teen slammed Zimmerman's head into the ground and threatened his life, Zimmerman's father claims.

In an exclusive interview with myFOXorlando, Robert Zimmerman detailed his son's account of the night, claiming Martin beat his son for over a minute and told him something along the lines of, "You're going to die tonight."

George Zimmerman has been the subject of a media firestorm since the shooting, with many calling for his arrest in the case.

George Zimmerman has claimed he shot Martin in self-defense, and so far has not been charged with any crime due to Florida's controversial "Stand Your Ground" law. The law allows the use of deadly force in self-defense if an individual reasonably feels threatened.

Martin's supporters, including a host of outspoken celebrities and civil rights leaders, don't believe George Zimmerman's story. They believe race played a role in the shooting, and are calling for George Zimmerman to be arrested and prosecuted.

In his first interview, Robert Zimmerman told myFOXorlando he decided to speak out for his son against the advice of police.

Robert Zimmerman claims his son was going to the store when he spotted Martin walking through his neighborhood. George Zimmerman, he said, found it odd the teen was walking in between the town homes on a rainy night, rather than on the street or on the sidewalk.

Since there had been multiple break-ins in the area, George Zimmerman decided to call police on the non-emergency number.

Police told George Zimmerman not to follow Martin, and asked him where he was. However, because he was behind the town homes he could not see the nearest address.

This is why, Robert Zimmerman claims, his son decided to keep following Martin, so he could obtain an address to give to police.

"(George Zimmerman) went to the next street, realized where he was and was walking to his vehicle," Robert Zimmerman said. "It's my understanding, at that point, Trayvon Martin walked up to him and asked him, 'Do you have a [expletive] problem?' "

Robert Zimmerman says his son told Martin he did not have a problem, and reached for his cellphone.

Then, Robert Zimmerman claims, Martin punched George Zimmerman in the face, breaking his nose and knocking him to the ground.

"Trayvon Martin got on top of him, and just started beating him," Robert Zimmerman claims. "In his face, on his nose, hitting his face on the concrete."

"After nearly a minute of being beaten, George was trying to get his head off the concrete, trying to move with Trayvon on him, in the grass. In doing so, his firearm was shown. Trayvon Martin said something to the effect of, 'You're going to die now,' or 'You're going to die tonight' or something to that effect," Robert Zimmerman said.

Robert Zimmerman said Martin continued to beat his son, and George Zimmerman at some point pulled out his gun and "did what he did."

Robert Zimmerman also responded to the 911 tape audio that has been widely publicized in the case, in which someone can be heard screaming for help. Martin's family claims it was their son screaming on the tape, and the fact that the screaming stopped after a gunshot is heard proves it.

"All of our family, everyone who knows George, knows absolutely that is George screaming," Robert Zimmerman said. "There's no doubt in anyone's mind."

When asked why the recording picked up screams for help but not the alleged threats by Martin, Robert Zimmerman said he does not know.

Robert Zimmerman also claims he doubts the account of the night from Martin's girlfriend, who claims she was talking with Martin on the phone before the incident.

"I don't believe that happened," Robert Zimmerman said. "I don't believe she was on the phone with him, and I find it very strange with the publicity involved... that all of a sudden, after three weeks, someone would remember that they were on the phone."

Robert Zimmerman said his son, who is reportedly in hiding, had a broken nose and injuries to his head after the incident.

"Currently he is not doing well," he said. "I don't know if those injuries are physical or mental, but he's not in good shape."

Robert Zimmerman says his family has received death threats, and he only spoke to myFOXorlando on the condition they did not show his face.

A former magistrate judge and Vietnam War veteran, Robert Zimmerman says this is one of the hardest things he has ever been through.

"Tough was being in Vietnam and other things in my life," he said. "This is way beyond anything I can imagine."

Zimmerman says he is hopeful his son will be cleared of all charges. He described George Zimmerman as a former Altar Boy who hoped to become a judge like his father.

He also said George Zimmerman once served as a mentor to two black boys and that his son is "colorblind."

Also Wednesday, a surveillance video shot after the shooting was released, showing George Zimmerman being led in handcuffs from a police car.

An attorney for Martin's family said it is obvious to him that Zimmerman did not have injuries to his face and head as his supporters have asserted.

"This certainly doesn't look like a man who police said had his nose broken and his head repeatedly smashed into the sidewalk," Ben Crump, an attorney for Martin's family, said in a statement after viewing the video. "George Zimmerman has no apparent injuries in this video, which dramatically contradicts his version of the events of February 26."

Crump called the video "riveting" and "icing on the cake" that Zimmerman should be held accountable for what happened.

Click here for more on the exclusive interview with Robert Zimmerman from myFOXorlando.com.

The Associated Press contributed to this report.