The parents of an unarmed black teenager shot dead by a neighbourhood watch helper in Florida are leading a rally in protest at the lack of an arrest.
Protests have been held across the US over the shooting of 17-year-old Trayvon Martin a month ago, and President Barack Obama mentioned the case last week.
Neighbourhood watch guard George Zimmerman reported Trayvon to police as suspicious and followed him, despite advice from an emergency dispatcher not to do so.
Mr Zimmerman told police he shot in self-defence, and Florida's controversial personal protection laws have meant he has not been arrested or charged.
Professional athletes will join civil rights leaders Jesse Jackson and Al Sharpton at the rally before a city leaders' meeting in the Orlando suburb of Sanford.
Trayvon's parents, Tracy Martin and Sybrina Fulton, were planning to address the commission.
Mr Zimmerman has not spoken in public about the shooting. His lawyer, Craig Sooner, has denied there was any racial motive.
A friend of Zimmerman said that Mr Zimmerman would tell the teenager's parents he's "very, very sorry" if he could.
Speaking on ABC's 'Good Morning America', Joe Oliver said Zimmerman was not a racist and has virtually lost his own life since the shooting.
"This is a guy who thought he was doing the right thing at the time, and it's turned out horribly wrong," he said.