NEW : He credits Cassidy Stay with saving 20 lives by alerting authorities . NEW : He says she played dead after being shot , then told police others were in danger . The girl speaks out for the first time , after her parents and 4 siblings were killed . He quotes from Harry Potter : ` ` Happiness can be found even in the darkest of times ''
NEW : Grandfather credits Cassidy Stay with saving 20 lives by alerting authorities . NEW : He says she played dead after being shot , then told police others were in danger . The teenager speaks out for the first time , after her parents and 4 siblings were killed . Cassidy quotes from Harry Potter : `` Happiness can be found even in the darkest of times ''