Dylann Roof: Charleston suspect 'illegally' bought weapon as result of failure in background check, says FBI

The FBI's James Comey said the weapon should not have been sold

Dylann Storm Roof poses with a confederate flag and a gun

Dylann Roof, the man charged with shooting dead nine people at a black church in Charleston, should not have been able to purchase the gun allegedly used in the attack and was only able to do so because of breakdowns in the FBI’s background-check system.

The FBI Director James Comey told reporters at FBI headquarters that the attack on the church could have been averted but for failures in the gun purchase screening system.

“This case rips all of our hearts out, but the thought that an error on our part is connected to a gun this person used to slaughter these people is very painful to us,” said Mr Comey.

Dylann Roof was arrested a day after the shooting in Charleston (EPA)

Nine people were killed on June 17 when they were attending bible study class at the Emanuel African Methodist Episcopal Church. Mr Roof has been charged with nine counts of murder and three of attempted murder.

In the days after the killings, a racist manifesto was found online along with 60 photographs of Mr Roof posing with the Confederate flag and standing at Confederate Civil War sites. Officials believe Mr Roof authored the document and became 'self-radicalised' after reading extremist material onine.

Among the images posted online was one of Mr Roof with a handgun that appeared to be a .45 Glock pistol, the type of firearm that was also found in his car when he was arrested the morning after the attack, the Washington Post said.

Pastor and politician Clementa Pinckney was among the nine killed at the Emanuel AME Church (Associated Press/David Goldman)

Mr Roof’s ability to purchase the gun has been a focus for investigators since the killings and it was reported that his father had given him the money for a weapon as a birthday gift.

The young man had been arrested for possession of narcotics in February, a felony charge that should have surfaced on criminal databases and prevented him from buying a weapon at a gun store.

But Mr Comey said the data was not properly entered in federal criminal justice computer systems, or had been mishandled by an analyst with the National Instant Criminal Background Check System.

"If she had seen that police report that purchase would have been denied," he said, according to the Associated Press.

He said he had only learned of the error on Thursday night and had told officials in South Carolina to meet with members of the nine people who were killed at the church to explain what had happened.

The revelation came on the day that the Confederate flag was lowered from outside the state house in the South Carolina capital, Columbia. The campaign to remove the banner gathered momentum in the aftermath of the shootings.