Cassie is about two different girls, both of whom died in the shootings at Columbine high school. Their names were Cassie Bernall and Rachel Joy Scott. They were both asked by the shooters, Eric Harris and Dylan Klebold if they believed in God, and they both said "yes", and were shot and killed for their beliefs.
Cassie's mother wrote a book called "She Said Yes", and Rachel's parents wrote a book called "Rachel's Tears". They're both beautiful books. Both girls were strong people, and stood up for what they believed in.