Story highlights Report: Freddie Gray case prosecutor Marilyn Mosby joined Prince on stage

Prince took a jab at previous curfews; told youth that fixing the "system" is their responsibility

Pop star urges fans to wear gray

(CNN) Pop star Prince made room for another color next to his signature purple in his Baltimore "Rally4Peace" concert Sunday -- and next to his music for dash of political gestures.

"Wear something gray," his promotional materials asked of patrons -- in remembrance of Freddie Gray, who died from severe spinal injuries after his arrest last month. On the concert poster, an illustration showed Prince wearing it, too.

After protests over Gray's death gave way to riots in the city, the singer-songwriter recorded a song called "Baltimore," dedicated to residents and to Gray, in which he calls for justice and peace.

"The system is broken," he shouted to the crowd at the Royal Farms Area. "It's up to you young folks to fix it."

Prince had announced he would come to town to play live. Audio from the concert was streamed free via the digital live music service TIDAL.

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