Violence mars Baltimore protest over Freddie Gray's death in police custody

Protesters rampaged through downtown Baltimore yesterday as the city's biggest demonstration yet over the death of a young black man in police custody turned violent.

More than 1,000 people had joined a peaceful 90-minute rally at city hall demanding justice for Freddie Gray, 25, who died last Sunday from spinal injuries, a week after he was arrested in west Baltimore.

But the mood shifted dramatically when scores of protesters moved to the vicinity of the Camden Yards baseball stadium, scene of an evening Baltimore Orioles-Boston Red Sox game.

Twelve people were arrested, police commissioner Anthony Batts told reporters.

"My family wants to say: 'Please, please stop the violence.' Freddie would not want this," Gray's sister Fredericka said.

Local television footage showed a crowd hurling traffic cones, soda bottles and trash cans at police officers, before randomly smashing store windows, looting merchandise and vandalising police cars.

Targets included a 7-Eleven convenience store, a Michael Kors fashion boutique, a financial services centre and a cellphone shop in Baltimore's landmark Lexington Market.