The trial began June 10 and has lasted five weeks, with nearly 60 witnesses and more than 60 exhibits, according to Michelle Kennedy, spokeswoman for the 18th Circuit Court.
Jurors began deliberations Friday afternoon. Judge Debra Nelson read instructions outlining the jury's three options: convict Zimmerman of second-degree murder or of manslaughter, or find him not guilty.
"All of us are depending on you to make a wise and legal decision," Nelson told the jurors.
If convicted of murder, Zimmerman, 29, would face up to life in prison. If convicted of manslaughter, he would face up to 30 years behind bars.
The courthouse is surrounded by satellite trucks and media, though it is still unclear whether a verdict will be issued today. A number of Martin supporters are chanting "Justice for Trayvon" and giving media interviews.
Kennedy says when the verdict is reached, she will announce the news on the 18th Circuit's Twitter feed, which has amassed over 3,000 followers.
Meanwhile, authorities express concern at the possible public reaction to an unfavorable verdict, as both Zimmerman and Martin have passionate supporters following the racially-charged case on television and social media.
The Broward County Sheriff's Office said it had made a "contingency plan" to respond to Miami-area incidents tied to a verdict.
"Freedom of expression is a constitutional right," the sheriff's office said. "While raising your voice is encouraged, using your hands is not."
But outside the courthouse, a pastor dismisses fears of rioting, saying that such a response would have happened "a year ago" when anger was still high. "We need to let this jury speak," he said.
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