CHICAGO (AP) -- The Rev. Jesse Jackson is urging people to avoid violence if George Zimmerman is found not guilty.

The civil rights activist is tweeting that message to his 20,000 Twitter followers as jurors deliberate Saturday for a second day in the racially charged case.

Former neighborhood watch leader Zimmerman is charged with second-degree murder in last year's slaying of a 17-year-old black teen in Sanford, Fla., Trayvon Martin.

Police in Florida say they're preparing for the possibility of mass protests or even civil unrest.

Jackson says people should "avoid violence because it only leads to more tragedies."

Jackson also says that should Zimmerman be found guilty people should avoid "inappropriate celebrations because a young man lost his life."

He says we seek "justice not revenge" from the judicial system.