FBI Director James Comey said the government's background check system failed to stop the alleged Charleston church shooter from purchasing a gun.
Comey said the FBI made a clerical error in part because of a law enforcement breakdown in paperwork, according to CNN.
Dylann Roof was arrested following the shootings June 17 at Emanuel African Methodist Episcopal Church in which nine people were killed. Roof is 21 years old and is from Shelby, North Carolina.
The suspect confessed to the killings, which happened inside the church at the end of a Bible study meeting Roof participated in.