A protestor is arrested after the judge declared a mistrial in the case of Baltimore police Officer William Porter in Baltimore, Maryland, Dec 16, 2015. Porter is the first of six officers to be tried in Gray's death from a neck injury sustained while in police custody. Marilyn Mosby, Baltimore City state's attorney, said the death of Freddie Gray was a homicide and that his arrest was illegal. Gray, 25, died a week after suffering a spinal cord injury while being arrested on April 12. [Photo/CFP]