Criminal charges will be filed in the death of a black man injured while in custody of Baltimore police, a state's attorney has announced.

The death of Freddie Gray, which has set off protests across the country, was a ruled a homicide following a "thorough" investigation, State's Attorney Marilyn Mosby said.

All six officers involved in Mr Gray's arrest on 12 April will be charged, including one officer who will face a count of second-degree murder.