Rihanna, Chuck D, 'The Wire' Stars & More React to Baltimore Riots

On April 12, 25-year-old Freddie Gray died of a spinal-cord injury while in the custody of Baltimore police. Now, more than two weeks later, as more details emerge about that day, the long-simmering tension between police and residents in the Maryland city has boiled over into violent riots and looting on Monday (April 27) -- so much so that the National Guard has been called in to help. It should also be noted that Monday's violence was preceded by days of protests that remained peaceful.

Walter Scott's Death Mourned by Janelle Monae, Big Boi & More

Musicians from Rihanna and Kelly Rowland to Big Boi and Charlie Daniels have taken to social media to address the protests -- whether imploring people to keep the peace or cheering on the activism.

David Simon -- who created the Baltimore-set HBO series The Wire -- took to his blog Monday to call for an end to riots and looting in the city. Many of the stars of his show also reacted with these tweets: