(CNN) -- Closing arguments resumed Friday in the murder case against George Zimmerman in the fatal shooting last year of Trayvon Martin -- a 17-year-old unarmed, black teenager -- by a 29-year-old neighborhood watch volunteer.
"Be careful," lead defense attorney Mark O'Mara told the jury as Zimmerman, dressed in a dark suit, looked on with interest. "This is a serious, serious matter for Mr. Zimmerman."
The prosecution presented its closing argument Thursday afternoon, and will get an opportunity for a rebuttal after the defense is finished.
The case then will go to the jury of six women, who have been sequestered and will decide whether Zimmerman should be acquitted or convicted of second-degree murder or manslaughter.
The defendant is accused of fatally shooting. Zimmerman has said he acted in self-defense.
Except for Zimmerman, there are no witnesses to the entire altercation that occurred on February 26, 2012, in Sanford, Florida.
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. "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.
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.