Protesters were to gather today outside a courtroom in Sanford as the trial begins. Inside, in an attempt to defuse fears of unrest, several seats have been set aside for black pastors to act as the "spiritual eyes and ears" of their communities.
"We are hoping for the best but preparing for the worst," said Paul Benjamin, a 50-year-old pastor who established the Love Sanford Project after last year's protests. "The mood out there is pretty combustible. Our role is to defuse the tensions in the community, to explain what is happening in court and to counter some of the negative stuff that's being spread on the streets. This case brought back a lot of painful memories for African-Americans."
Tensions flared last month when Mark O'Mara, Zimmerman's lawyer, released texts and photographs from Trayvon's mobile phone that appeared to show him as a devotee of guns, fighting and marijuana. While O'Mara was seeking to have the material introduced as evidence, saying it indicated the teenager was prone to violence and might have been on drugs, critics accused him of attempting to prejudice a jury.
What is not in doubt is that Zimmerman shot Trayvon that night in February as the teenager walked to the home of his father's fiancee from a convenience store.
Zimmerman had cuts to his head, bruising and possibly a broken nose; Trayvon lay bleeding to death. Just about every other detail is disputed.
At the heart of the case is whether Zimmerman was a racist vigilante who presumed an innocent black boy in a hoodie was a menacing criminal; or whether he fired the gun that he was legally carrying in an attempt to save his life after being attacked.
The case escalated after the local police force, white-led at the time, accepted Zimmerman's explanation that he killed Trayvon in self-defence and no charges were brought.
"Justice for Trayvon" marches were organised across the country. Zimmerman and his family went into hiding amid death threats. State prosecutors intervened to charge him with second degree murder, an offence that carries up to 25 years.
"When Trayvon was killed, it was the straw that broke our backs," said Francis Oliver, 69, a historian whose family moved to Sanford in 1947, the same year Jackie Robinson, the first black player in professional baseball, was run out of town by racist whites.
"Young black men had been killed here for years and the police did not investigate, they didn't care. But with Trayvon, we were not going to take it anymore."
In areas of Sanford with a white majority, Zimmerman has plenty of supporters, though few are willing to be quoted publicly. An exception is Frank Taaffe, 56, a close friend and fellow neighbourhood watch activist.
"George was not racially profiling that night. He cared about the neighbourhood and was worried as there had been a lot of burglaries and saw this kid acting suspiciously. This case has been so polarised that the other side doesn't want to take the cotton out of its ears and listen.
"This was a 17-year-old African-American male in great shape. He saw George and he jumped George. He saw George's gun and he would have killed George ... Someone's child has been killed. But George was only defending his community and himself."
