The self-appointed neighborhood watch leader who gunned down an unarmed black teen may have uttered a racial slur before the shooting as he spoke with Florida police dispatchers, WFTV.com reported.

The tape of George Zimmermans 911 phone call is unclear, but he may have said f---ing c--ns, under his breath as he followed Trayvon Martin. The dispatcher told him he did not have to follow the teen, but the confrontation took place moments later.

Zimmerman, 28, has not been charged in the Feb. 26 shooting. He said he shot Martin, 17, in self-defense. Police called Zimmerman white, but his family says he is Hispanic.

The killing sparked heated reaction.

At a town hall meeting Tuesday evening in Sanford, Fla., civil rights leaders urged residents to remain calm but demand that the shooter be arrested.

The case has ignited a furor against the police department of this Orlando suburb of 53,500 people, prompting rallies and a protest in Gov.