As the jury got the murder case, police in this Orlando suburb went on national television to plead for peace in Sanford and across the country, no matter what the verdict.
"There is no party in this case who wants to see any violence," Seminole County Sheriff Don Eslinger said. "We have an expectation upon this announcement that our community will continue to act peacefully."
During closing arguments, Zimmerman's lawyers put a concrete slab and two life-size cardboard cutouts in front of the jury box in one last attempt to convince the panel Zimmerman shot the unarmed black 17-year-old in self-defense while his head was being slammed against the pavement.
Attorney Mark O'Mara used the slab to make the point that it could serve as a weapon. He showed the cutouts of Zimmerman and Martin to demonstrate that the teenager was considerably taller. And he displayed a computer-animated depiction of the fight based on Zimmerman's account.
He said prosecutors hadn't met their burden of proving Zimmerman's guilt beyond a reasonable doubt. Instead, he said, the case was built on "could've beens" and "maybes."
"If it hasn't been proven, it's just not there," O'Mara said. "You can't fill in the gaps. You can't connect the dots. You're not allowed to."
In a rebuttal, prosecutor John Guy accused Zimmerman of telling "so many lies." He said Martin's last emotion was fear as Zimmerman followed him through the gated townhouse community on the rainy night of Feb. 26, 2012.
"Isn't that every child's worst nightmare, to be followed on the way home in the dark by a stranger?" Guy said. "Isn't that every child's worst fear?"
One juror, a young woman, appeared to wipe away a tear as Guy said nothing would ever bring back Martin.
The sequestered jury of six women - all but one of them white - will have to sort through a lot of conflicting testimony from police, neighbors, friends and family members.
Jurors deliberated for three and a half hours when they decided to stop Friday evening. About two hours into their discussions, they asked for a list of the evidence. They will resume deliberations Saturday morning.
Witnesses gave differing accounts of who was on top during the struggle, and Martin's parents and Zimmerman's parents both claimed that the voice heard screaming for help in the background of a 911 call was their son's.
Zimmerman, 29, is charged with second-degree murder, but the jury will also be allowed to consider manslaughter. Under Florida's laws involving gun crimes, manslaughter could end up carrying a penalty as heavy as the one for second-degree murder: life in prison.
The judge's decision to allow the jury to consider manslaughter was a potentially heavy blow to the defense: It could give jurors who aren't convinced the shooting amounted to murder a way to hold Zimmerman responsible for the killing.
To win a manslaughter conviction, prosecutors must show only that Zimmerman killed without lawful justification.
O'Mara dismissed the prosecution's contention that Zimmerman was a "crazy guy" patrolling his townhouse complex and "looking for people to harass" when he saw Martin. O'Mara also disputed prosecutors' claim that Zimmerman snapped when he saw Martin because there had been a rash of break-ins in the neighborhood, mostly by young black men.
The defense attorney said Zimmerman at no point showed ill will, hatred or spite during his confrontation with Martin - which is what prosecutors must prove for second-degree murder.
"That presumption isn't based on any fact whatsoever," O'Mara said.
In contrast, prosecutors argued Zimmerman showed ill will when he whispered profanities to a police dispatcher over his cellphone while following Martin through the neighborhood. They said Zimmerman "profiled" the teenager as a criminal.
Guy said Zimmerman violated the cornerstone of neighborhood watch volunteer programs, which is to observe and report, not follow a suspect.
Zimmerman's account of how he grabbed his gun from his holster at his waist as Martin straddled him is physically impossible, Guy said.
"The defendant didn't shoot Trayvon Martin because he had to; he shot him because he wanted to," Guy said. "That's the bottom line."
But to invoke self-defense, Zimmerman only had to believe he was facing great bodily harm, his attorney said. He asked jurors not to let their sympathies for Martin's parents interfere with their decision.
"It is a tragedy, truly," O'Mara said. "But you can't allow sympathy."
With the verdict drawing near, police and city leaders in Sanford and other parts of Florida said they have taken precautions for the possibility of mass protests or even civil unrest if Zimmerman, whose father is white and whose mother is Hispanic, is acquitted.
There were big protests in Sanford and other cities across the country last year when authorities waited 44 days before arresting Zimmerman.
About a dozen protesters, most of them from outside central Florida, gathered outside the courthouse as the jury deliberated. Martin supporters outnumbered those for Zimmerman.