SANFORD, Fla. -

Attorneys representing George Zimmerman present their closing arguments on Friday, as jurors begin deliberating.

[WATCH/CHAT LIVE:  Tony Pipitone in courtroom | SPECIAL SECTION:  Zimmerman trial]

Zimmerman, 29, is charged with second-degree murder in the death of Trayvon Martin, who was shot and killed in a Sanford gated community in February 2012. 

Attorney Mark O'Mara began his closing arguments by casually thanking the jury before bringing up Zimmerman and put his hand on Zimmerman's shoulder as he discussed the presumption of innocence. He made references about Zimmerman moving to Florida and how he's married.

O'Mara told the jury "you don't know how to apply a standard reasonable doubt, you just don't." O'Mara said lawyers know how to apply reasonable doubt because they're used to it, but that he worries the jury will default back to their first impression of Zimmerman.

O'Mara then put on sunglasses and a pinkie ring to demonstrate how first impressions can influence your opinion and cloud your judgment.

"I think you have to be absolutely vigilant," O'Mara said to the jury.

Nine minutes into O'Mara's closing arguments, Martin's family walked in.

O'Mara told jurors they are not allowed to make a verdict based on assumptions.

"A just verdict is one without assumptions," O'Mara said, adding that Zimmerman is "not guilty of anything but protecting his own life."

O'Mara then attacked the prosecution's lack of definitive testimony.

"How many 'could-have-beens' and 'what-ifs' did you hear from prosecutors?" They should say 'without question,' certainty," O'Mara said.

O'Mara then brought out a poster explaining burden of proof to the jurors with the continuum of doubt: highly unlikely, less than likely, probably not, unlikely, may not be, perhaps, suspected, possibly guilty, etc.

"George Zimmerman is not guilty if you have reasonable doubt he acted in self-defense," O'Mara said.

He then discussed the state calling Zimmerman a "wannabe cop." O'Mara said Zimmerman did want to be a cop, as well as a prosecutor, lawyer and a helper.

O'Mara told jurors the state withheld a sixth non-emergency call Zimmerman made that didn't support the state's theory.

"The state wants you to hear 'I hate these young black males' in Zimmerman's calls," O'Mara said, mocking the suggestion that Zimmerman was frustrated on the non-emergency calls.

O'Mara then brought out a 10-foot-long timeline of Zimmerman call, showing "he's running" coinciding with when Martin's call with Rachel Jeantel disconnects the first time.

"The person who decided this was going to continue, that it was going to become a violent event was the guy who didn't go home when he had the chance to," O'Mara said.

O'Mara said the dispatcher told Zimmerman, "let me know if he (Martin) does anything else."

O'Mara then played the computer-animated reenactment that Judge Debra S. Nelson ruled couldn't be used in the trial as evidence, but could be used as demonstrative in closing arguments. O'Mara showed jurors where the defense "contend" Zimmerman was punched in the nose.

With the animation, the jury visualized a scene they have only seen in photos. The animation was also lined up with 911 calls. The jury will not be able to take back the animation to deliberate. 

O'Mara then started a stopwatch and let jurors sit in silence to demonstrate four minutes between Martin starting to run and the first 911 call.

"That four minutes is how long Trayvon Martin had to run (back home)," O'Mara said, calling it a "football throw length away." O'Mara suggested Martin ran, plotted and four minutes later, executed his attack on Zimmerman.

O'Mara then discussed Zimmerman's statement to his neighbor, Jonathon Manalo, who he told to call his wife. "Tell her I shot someone," O'Mara said Zimmerman told Manalo, not thinking of how insensitive it might sound a year-and-a-half later.

"We have factual innocence," O'Mara said of Zimmerman being innocent. O'Mara told the jury there was no evidence of Zimmerman being a "cop wannabe" because he turned down the opportunity to be part of citizen's patrol.

O'Mara also showed pictures of witnesses when talking about their testimony. The state didn't use pictures.

He then brought out life-sized wooden figures showing the difference between Martin and Zimmerman's height and showed pictures of Martin to the jury, saying "this is the person who attacked Zimmerman."

O'Mara said Zimmerman had to have a reasonable fear of great bodily harm to justify the use of deadly force, based on circumstances at the time.

O'Mara finished out his closing argument by saying what the state hasn't proven as part of their burden.

He brought out a chunk of concrete sidewalk that he says Martin used as a weapon and said, "that is not an unarmed teenager."

"I really feel like that would have convinced you beyond reasonable doubt that Zimmerman is innocent," O'Mara said.

O'Mara said the jury has an easy decision--to say they have reasonable doubt the state didn't convince them Zimmerman should be convicted of second-degree murder.

"Thank you for the time. Thank you for the attention," O'Mara said. "Because you given us what we needed ... which was your attention."

Prosecutor John Guy started out the state's 45-minute rebuttal after the defense's closing by discussing the human heart.

"The human heart, it has a great many functions ... it moves us," Guy said, playing on the sympathy of the jury by asking them to look into the heart of Martin and Zimmerman to know what happened.

"I'm asking you to use your common sense. Use your heart," Guy said.

"It's not my voice that matters, it's your voice," Guy continued. "He put on a timeline that was 10 feet long and the only thing that he skipped was the words on the bottom of the screen," showing what Zimmerman said to the non-emergency dispatcher.

Guy then described Jeantel as the "witness that was on the phone with the real victim of the case, Trayvon Martin, up until the time of his death."

"Was that child not in fear when he was running from that defendant?" Guy said. "Isn't that every child's worst nightmare to be followed on the way home in the dark by a stranger?"

Guy highlighted inconsistencies in Zimmerman's testimony, asking why Zimmerman "had to lie" if he wasn't doing anything wrong, and said Zimmerman's lies is "why we're here."

"Trayvon Martin may not have had the defendant's blood on his hands, but George Zimmerman will forever have Trayvon Martin's on his," Guy said.

Guy then rebutted the defense's claim Martin was running in the 4 minutes.

"What was George ZImmerman doing for two minutes between ending non-emergency call and Rachel Jeantel hearing the struggle?" Guy asked. "Four minutes is not the amount of time Trayvon Martin had to run home."

Guy said the defense's claim that if Martin was on top of Zimmerman he couldn't have reached Zimmerman's gun, claiming it was a "physical impossibility." Martin could have been backing away. Guy said.

Zimmerman's injuries were also discussed. Guy said if Zimmerman's head were smashed, his injuries wouldn't look like they did.

"Was Zimmerman injured seriously?" Guy said. "Not close. Not close."

Guy then referred to Zimmerman as "Mr. Stay Puff" and "Mr. Softie" and said that Zimmerman had to make Martin sound "menacing" to justify what he did.

"This case is not about 'stand your ground' it's about 'stay in your car,' Guy said.

Guy pointing at Zimmerman, said Zimmerman "chose everything." Guy said Zimmerman got out of the car "with his loaded gun" and shot Martin through the heart. 

"Is that not anything?" Guy said. "Your verdict won't change the past but it will define it." Guy said Martin is "entitled" to a guilty verdict.

Guy then referred to Zimmerman's interview on the 'Hannity' show, when he said the shooting was "God's plan."

O'Mara objected to a part of Guy's rebuttal where he discusses reasonable doubt. Nelson said that she will instruct the jury about the reasonable doubt law.

"This case is not about race. It is about right and wrong," Guy said, ending his rebuttal with high emotions and thanking the jury.

A day earlier, prosecutors made the case that Zimmerman assumed Martin was a criminal up to no go when he confronted him in his neighborhood. A scuffle followed, and Zimmerman fired his gun.

The jury will also be able to consider a lesser charge of manslaughter for Zimmerman. Nelson's ruling to allow consideration of the manslaughter charge came despite the objections of Zimmerman's lawyers.  Nelson, however, did not allow the jury to consider a third charge of third-degree murder based on child abuse, despite the state's request.

The court on Thursday also released jury instructions, which the state and defense agreed upon after hours of argument.  The all-women jury will read the 27-page document before deciding Zimmerman's fate.

The defense claims Zimmerman killed Martin in self-defense and will give its closing arguments a day after the prosecution spent two hours summarizing its case.

[FREE: Zimmerman App | PICS: Murder Trial | READ: State witness guide | Defense witness guide]

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