George Zimmerman, accused of hatefully gunning down an African-American teenager, isn't guilty of anything "except protecting his own life," the former neighborhood watch volunteer's attorney said Friday in closing arguments in the Sanford, Florida, man's murder trial.

"How many 'coulda beens' have you heard from the state in this case," attorney Mark O'Mara asked. "How many 'what ifs' have you heard from the state in this case? They don't get to ask you that. No, no, no."

"Do not give anybody the benefit of the doubt except for George Zimmerman," O'Mara said.

Zimmerman, 29, is accused of second-degree murder for killing the 17-year-old on February 26, 2012. Prosecutors call Zimmerman a frustrated wannabe police officer who took the law into his own hands.

They say he decided on his own that Martin was one of the criminals who had been victimizing his neighborhood, tailed him against the advice of police dispatchers, and then wrongly shot him to death.


In a closing argument that spanned more than three hours, O'Mara tried to discredit that image, saying Martin was the one who stalked Zimmerman and emerged from the darkness to pounce on Zimmerman, pinning him to the ground and slamming his head into the concrete sidewalk.

"That's cement; that is a sidewalk," O'Mara said, lugging a heavy block of cement to a spot on the floor in front of the jury. "And that is not an unarmed teenager with nothing but Skittles trying to get home. That was somebody who used the availability of dangerous items, from his fist to the concrete, to cause great bodily injury against George Zimmerman."

With O'Mara's arguments over, only a shorter prosecution response remained before the six-woman jury gets the case.

The case sparked anger and debate nationwide about race relations and gun control and led to protests and rallies calling on authorities to charge Zimmerman, who is Hispanic, in Martin's death.

O'Mara is expected to complete his arguments Friday morning. After that prosecutors will get another chance to talk to the six-woman jury before the case goes to them.

Judge Debra Nelson ruled Thursday that they will be allowed to consider manslaughter in addition to the original second-degree murder charge.

The prosecution

State prosecutor Bernie de la Rionda has argued that Zimmerman's account that he fired his gun because he feared for his life does not hold up.

"He brought a gun to a struggle, to a fight that he started ... wanting to make sure the victim didn't get away," the prosecutor said in his closing argument Thursday. "And now he wants you to let him off because he killed the only eyewitness, the victim Trayvon Martin, who was being followed by this man."

Zimmerman, 29, did not testify when his defense team rested its case on Wednesday, but his words were front-and-center a day earlier.

The prosecutor sought to pick apart interviews Zimmerman had given to police and in the media.

Why would a scared man get out of his car and walk around after being told by a 911 dispatcher not to follow the victim? Did Zimmerman walk toward Martin, or did Martin come after him -- as he seemingly said both? Should he have had more than a bloody nose and scratches on his head if he'd had his head slammed on the ground by the victim?

"(Zimmerman) always has an excuse, or they catch him in a lie," de la Rionda said.

The trial kicked off June 24 with opening statements. The prosecution called 38 witnesses in nine days while the defense took parts of four days to call its witnesses.

The defense

O'Mara and his team have maintained that Zimmerman is not racist but fought Martin in self-defense during a struggle in which the teenager pummeled him. Martin was visiting his father who lived in the neighborhood, which Zimmerman said had experienced recent break-ins.

On the day the defense rested, O'Mara said Zimmerman was considering testifying.

"He really wanted to talk to his jury and tell them what he did, why he did it and what he was facing when he made that decision to fire the shot," O'Mara told CNN's "AC 360."

But there was no need for him to testify, he said, because the state had not proven its case beyond a reasonable doubt.

Though expressing confidence in his defense, O'Mara said he fears that the jury might consider a compromised verdict.

"We want a verdict based upon the facts and the law and that's an acquittal," he said.

The man tasked with representing Zimmerman said that, whatever the outcome, his client will not feel safe.

"There are a percentage of the population who are angry, they're upset, and they may well take it out on him," he said.

A nation, divided

The case has divided the nation on issues of race and gun laws.

After the shooting last year, police did not immediately charge Zimmerman, citing Florida's "Stand Your Ground" law. The law allows those who believe they are in imminent danger to use deadly force to protect themselves.

Protesters took to city streets in support of the teen's family. Some wore hoodies, as did Martin the night he was killed.

In April last year, the Florida state prosecutor stepped in and charged Zimmerman.

Supporters have maintained that the black teen was a victim of racial profiling, tailed by the defendant over the objection of police dispatchers, then wrongly shot. Zimmerman is Hispanic.

Mother vs. mother

In testimony, the mother of the victim and the mother of the defendant identified an anguished voice on a 911 tape as having come from their respective sons. On the night of the killing, as residents made 911 calls to report the altercation, yells for help can be heard in the background.

Various neighbors called 911 and described what they saw and heard. But none of them saw the entire altercation, according to testimony.

Some described hearing a gunshot.

The prosecution has said the absence of Martin's DNA on the pistol Zimmerman was carrying disproves defense arguments that the teen grabbed the gun during the struggle.

Foam dummy, mystery

The deliberations cap a week of drama that included both sides using a foam dummy to describe the struggle.

Each side has used unusual means in an effort to prove its case.

Thursday's closing argument marked the return of the dummy that had appeared a day earlier when O'Mara used it to show jurors the competing theories of what happened the night Martin died.

This time it was de la Rionda's turn to characterize Zimmerman's account.

While the teen allegedly punched him, slammed his head and covered his neck and mouth,

The prosecutor questioned how Martin -- while he was allegedly punching Zimmerman, slamming his head onto the pavement and covering his neck and mouth -- could have also reached for the gun that Zimmerman said was in a holster inside his waistband, as the defense suggested.

HLN's Grace Wong, Graham Winch, Amanda Sloane, Jonathan Anker and Anna Lanfreschi and CNN's John Couwels and Mayra Cuevas contributed to this report.