Officials appealed for calm after the first effort to convict an officer in Freddie Gray's death from a broken neck in a Baltimore Police van ended with a hung jury and a mistrial.

Small crowds protested late on Wednesday along streets lined with police officers. The situation was quiet at the intersection where the worst rioting happened in April as parts of West Baltimore were set on fire.

William Porter's mistrial is a setback for prosecutors trying to respond to a citizenry frustrated by violent crime and allegations of police misconduct. Homicides have soared, and the pressure on city officials has been unrelenting since Baltimore City State's Attorney Marilyn Mosby charged six officers in Gray's death.