In September, former Florida A&M University football player Jonathan Ferrell, 24, was gunned down by a police officer while looking for help at a woman's home after a car crash.
In 2012, Trayvon Martin, 17, was unarmed when he was shot and killed by George Zimmerman. Zimmerman was acquitted of the murder this summer.
Rideout said McBride's family has been grateful for the outpouring of support.
"We're getting overwhelming support from all over the world. People are hurting from Detroit to New York to Chicago to Alabama to St. Louis," he said.
"People are hurt because this 19-year-old young lady was shot down viciously and defenselessly without a weapon in her hand and without being an alleged criminal. She didn't do anything."