A Killer's Troubled Road to Radicalization

The people who know Dylann Roof — the people who watched his progression from a sweet child to a disturbed man — are struggling with guilt. How could they have missed the signs? Could they have done something to prevent the deaths of nine innocents at the Emanuel African Methodist Episcopal Church?
How did it all happen?
Roof himself offers no answers. He sits in North Charleston's Sheriff Al Cannon Detention Center, charged with the murders, his $1 million bail far beyond reach. Court documents and nearly two dozen interviews show his early childhood was troubled and confused as well, as he grew up in an unstable, broken home amid allegations of marital abuse and infidelity.
He apparently fell under the thrall of racist websites. But how and why are questions that remain unanswered.