Story highlights

Dylann Roof, 21, waives extradition to South Carolina; he was arrested Thursday in Shelby, North Carolina

"There is no greater coward than a criminal who enters a house of God and slaughters innocent people," says president of the NAACP

Eight people died at the scene in downtown Charleston, South Carolina; a ninth died at a hospital

Charleston, South Carolina CNN  — 

Before he allegedly opened fire on members of a Bible study group at a church in Charleston, South Carolina, Dylann Roof sat with them. He might have prayed with them.

A Snapchat video from Wednesday night at the historic African-American church shows Roof at a table with the small group. Nothing in the footage suggests the carnage to come.

Police say Roof shot and killed nine people inside the historic Emanuel African Methodist Episcopal Church, near the heart of Charleston’s tourist district. Eight died at the scene; a ninth died at a hospital.

Authorities were shocked not only by the killings but that the violence occurred in a house of worship.

“People in prayer Wednesday evening. A ritual, a coming together, praying, worshiping God. An awful person to come in and shoot them is inexplicable,” said Charleston Mayor Joe Riley.

Six women and three men were killed, including the church’s politically active pastor, the Rev. Clementa Pinckney.

Sylvia Johnson, a cousin of Pinckney, said she heard about what happened inside the church from a survivor, a close friend.