The jury in George Zimmerman's murder trial will start its second day of deliberations on Saturday morning.

The panel discussed the case for about three and a half hours on Friday before adjourning without reaching a decision in the shooting of 17-year-old Trayvon Martin.

Zimmerman says he shot the unarmed black teenager in self-defense after he was attacked. Prosecutors say he was a wannabe cop who took the law into his own hands when he saw someone he thought was suspicious in his neighborhood.

Zimmerman is charged with second-degree murder, but jurors can also choose manslaughter. A conviction on either charge could mean life in prison.

Police and civic leaders have urged people to remain calm after the verdict, no matter what the jury decides.