charleston shooting
Police lead suspected shooter Dylann Roof, 21, into the courthouse in Shelby, North Carolina Jason Miczek/reuters

An astonishingly racist American white nationalist organisation is insisting that the young South Carolina gunman charged with killing nine black parishioners at bible study had some "legitimate grievances".

"We of course categorically condemn his act, but that doesn't mean his motives weren't entirely legitimate," Jared Taylor of the Council of Conservative Citizens (cofCC) tells ABC News.

Taylor talked to ABC after the group issued a statement condemning incidents of "black-on-white crime" in the wake of accused killer Dylann Roof's alleged attack on the parishioners of the Emanuel African Methodist Episcopal Church in Charleston.

"We utterly condemn Roof's despicable killings, but they do not detract in the slightest from the legitimacy of some of the positions he has expressed," noted the statement. "Ignoring legitimate grievances is dangerous." The site also warns that "silence" about "black-on-white crime" only "makes acts of murderous frustration more likely."

"It's taboo to even talk about this," Taylor told ABC. "Even as we're speaking right now, a white woman is probably being raped by a black man ... If we're going to have any kind of honest discussion of race in this country, you're going to have to talk about black-on-white violence."

Roof, 21, named the group in a manifesto that law enforcement authorities believe he penned before the attack.

In the missive, Roof purportedly talks of typing the words "black-on-white crime" into an online search, declaring "I have never been the same since that day. The first website I came to was the Council of Conservative Citizens. There were pages upon pages of these brutal black on White murders. I was in disbelief. At this moment I realised that something was very wrong."

Witnesses say Roof told his victims that he had to act before he allegedly opened fire because "you rape our women and are taking over our country and you have to go."

Taylor said Roof has never been a member of the Council of Conservative citizens, and no one in the group knows him.

Heidi Beirich of the Southern Poverty Law Center, which has branded the CofCC a hate group, noted: "This idea that black men are raping white women, it goes to the heart of the white supremacist thing. I mean basically the propaganda that they believe are that black people are violent, sexual deviants, everything bad that you can say about a population."

At least three Republican presidential candidates — Rick Santorum, Ted Cruz and Rand Paul — have now opted to return campaign donations from Earl Holt, the head of the CofCC.