A key day for the prosecution a day to try, try and knock down the notion thatGeorge Zimmerman fired the shot that killed Trayvon Martin in self-defenseduring a life-and-death struggle and not a garden variety brawl. Central tothat prosecution effort, refuting Zimmerman's claims that Trayvon Martinrepeatedly slammed his head into the sidewalk.

 

Now in a moment our own forensic expert weighs in along with our legal panel,but first Martin Savidge has that and some of the day's other big developments in court.

 

Prosecutors switch from using George Zimmerman's words against him to using his injuries.

 

Are the injuries to the back of the defendant's head consistent of having beenrepeatedly slammed into a concrete surface?

 

No.

 

 

The medical examiner testified that Zimmerman's wounds were notlife-threatening and didn't reflect a person whose head had repeatedly beenslammed against the ground. The key reason Zimmerman has given for shootingTrayvon Martin.

 

 

How would you classify the injuries to the defendant's head?

 

 

They were not life threatening. They were very insignificant. They did notrequire any sutures(缝合) to be applied to Mr. Zimmerman, so as I would refer to theminsignificant injuries.

 

 

On cross-examination defense attorney Mark O'Mara implied Valerie Rao owed herjob to the special prosecutor in the Zimmerman case and then walked Rao backfrom some of her findings.

 

 

And if I get it right, it's your position it's at least consistent that GeorgeZimmerman may have only received as little as three, did you call, what termdid you use? Smashing? Or …

 

Sorry?

 

 

Slamming. Three slamming into cement, correct?

 

 

I didn't, I didn't use the word slamming.

 

 

I'm sorry, I thought it was your word.

 

 

No, I got that from the reenactment(再扮演).

 

 

What would you use to describe what happened to the head that you say hitcement?

 

Impact.

 

Impact. So it's your position that there are at least three impacts betweenthat head and cement?

 

Yes.

OK.

 

Concrete.

 

Earlier, Zimmerman's best friend took the stand. It was Mark Osterman who firstconvinced Zimmerman to buy a gun. He also housed George and Shelley Zimmermanfor a time after the shooting and wrote a book about the case.

 

 

You wrote a book and where you quoted what the defendant George Zimmerman toldyou, correct?

 

Correct.

 

And you recall on that book writing, "Do you have a problem?" That'swhat he said Trayvon Martin said?

 

Right, correct.

 

In that book, Osterman says Zimmerman said Martin tried to reach for the weaponon his hip, actually touching the gun.

 

The defendant is claiming that the victim actually grabbed the gun, correct?

 

That was my understanding, that he grabbed the gun.

 

But a latent(潜在的；隐约的指印) print technician testified she found no trace of Trayvon Martin'sprints on the slide(滑动部件) of the gun, but conceded rain or other factors could wash printsaway.

 

So that fingerprints may have existed on an item that you would lift a latentfrom and there'd be no latent whatsoever, correct?

 

That's correct.

 

Even though the gun has been handled by one, two or three people.