he says this was a mistake. they are all sick that it happened. the man who confessed to gunning down nine people inside a south carolina church should never have been able to buy the .45 caliber gun used in the slaughter. that emission coming from fbi. they made a mistake during his background check. according to law enforcement officials, within days after the shooting agents on the ground knew something was amiss and suspected that his arrest record should have prohibited the gun purchase. >> that just shows how a bureaucratic mistake can cost human life. >> reporter: the director says the fbi examiner during his background check didn't discover he had previously admitted to illegally possessing drugs when he was arrested in late february. that would have permitted him from passing the background check. >> there is a revel ligsation that