(CBS News) SANFORD, Florida - The defense of George Zimmerman rests on a violent fight that he said occurred before he fired the shot that killed Trayvon Martin.
Zimmerman is neighborhood watch volunteer at the center of the case. It was almost five weeks that Martin, the unarmed 17-year-old, was killed after Zimmerman found him suspicious. We don't know what happened immediately immediately before the shot was fired. CBS News correspondent Mark Strassman has new evidence in the case.
Trayvon Martin was buried in Miami with a gunshot wound to his chest. But otherwise, according to Richard Kurtz, the funeral director who prepared Martin for burial, his body showed no injuries.
"We could see no physical signs like there had been a scuffle [or] there had been a fight," he said. "The hands -- I didn't see any knuckles, bruises or what have you. And that is something we would have covered up if it would have been there."
And as a surveillance tape shows, George Zimmerman in handcuffs, 40 minutes after he killed Trayvon Martin. He seemed to show no apparent injuries, either.
Yet Zimmerman claims Martin beat him and threatened his life, so he shot the teenager in self-defense.
But Ben Crump, the lawyer for Martin's parents, said the video shows a murderer.
"Look at that video," he said. "Do you see any blood on his head? He said he broke his nose. Look at that video. And look at how easy he walks out of the car."
Zimmerman, a crime watch volunteer, thought Martin looked suspicious, called police, and followed Martin along a street and around a corner.
Robert Zimmerman, the gunman's father, told WOFL-TV in Orlando that Martin suddenly confronted his son.
Watch the full interview with Richard Kurtz, the funeral director who prepared Trayvon Martin's body for burial, below:
"At that point he was punched in the nose," he said. "His nose was broken. and he was knocked to the concrete. Trayvon Martin got on top of him and just started beating him in the face and in the nose, hitting his head on the concrete."
Police reports noted Zimmerman was "bleeding from the nose and the back of the head." But a closer look at Zimmerman shows no obvious head or face injuries. At one point, an officer does check the back of his head.
Martin's family contends this video proves police never wanted to arrest Zimmerman.
And Cheryl Brown said a widespread perception is wrong: Sanford police wanted to charge Zimmerman. She identified Chris Serino as the lead investigator who questioned people in the neighborhood.
"Detective Serino -- did you have the sense when he interviewed you that he thought it was a killing in self-defense?" Strassmann asked Brown.
"No, because he actually stated to me in my family room that 'we do not believe it was self-defense and we need to prove it,'" said Brown.
A special prosecutor will now decide whether Zimmerman deserves to be charged. Zimmerman's father insists his son is also a victim here.
"...They are just making up stuff that are not true about George. How he is being portrayed is an absolute lie."
Robert Zimmerman said Martin beat his son for more than one minute. And when his son fired his .9-mm, Robert Zimmerman said it was because he had no choice.