FBI Director James B. Comey said Friday that agency employees should have rejected Dylann Roof's attempt to purchase a gun because Roof had earlier been arrested for possession of drugs.
Authorities charge that Roof killed nine people at the Emanuel African Methodist Episcopal Church in Charleston, S.C., in a racially motivated attack.
"The bottom line is clear," Comey said. "Dylann Roof should not have been allowed to purchase the gun that day."
He said Roof went to a West Columbia, S.C., gun shop on April 11 to buy the gun. Under federal law, the FBI had three days to block the purchase.