Gray, 25, was arrested on April 12 for possession of a switchblade. By the time Gray arrived at the police station, his condition was critical. Within an hour of his arrest, Gray had fallen into a coma and died on April 19.
The police officers involved in the accident denied using force against Gray during or after the arrest. However, witnesses claim that Gray was screaming in pain while he was being dragged to the police van.
Thousands of activists held demonstrations in the city, calling for release of the video footage showing the events while Gray was being held in custody.
People marched on the street to protest police brutality and racial discrimination. The protests turned violent, and an angry crowd set police cars on fire and damaged several local shops.
Baltimore police Col. Darryl D. DeSousa said that more than two dozen rioters were arrested.
Over the past years, several major rallies against police brutality and racial profiling have been held across the United States, triggered by numerous police killings of unarmed African-Americans.
Following the Monday protests, Baltimore Mayor Stephanie Rawlings-Blake declared a state of emergency and announced a one-week curfew in the city from 10 p.m. to 5 a.m.