The city of Sanford has been getting increasingly tense as the decision neared. Six shots were fired into an empty police cruiser earlier this week in the neighborhood where Martin was killed.
The New Black Panther Party offered a $10,000 bounty for Zimmerman and his lawyers said Zimmerman had received death threats.
The New Socialist Movement, a white supremacy group, said they were going to patrol Sanford to protect whites, and racists comments about the shooting have sprung up on social media sites.
Debate over the shooting became so widespread that even President Obama commented, saying if he had a son he would have looked like Trayvon Martin.
On his website, Zimmerman released a statement about the shooting this week, calling the incident a "life-altering event."
"As a result of the incident and subsequent media coverage, I have been forced to leave my home, my school, my employer, my family and ultimately my entire life," he wrote.
In a written statement to police on the night of the shooting, Zimmerman said that he'd called 911 to report a suspicious man and that as he returned to his car, Martin attacked him. Zimmerman said that Martin punched him in the nose and knocked him down, slammed his head on the ground and tried to take his gun.
The police report noted that Zimmerman was bleeding from the back of the head and nose. His lawyer said later that Zimmerman suffered a broken nose.
After Zimmerman received medical attention, it was decided that he was in good enough condition to travel in a police cruiser to the Sanford police station for questioning. He was not arrested.