Police believe Roof, who authorities say was motivated by racial hatred against African-Americans, acted alone. An uncle of his said Roof, whose social media profile suggests a fascination with white supremacy, received a gun as a 21st birthday present in April.
Sylvia Johnson, a cousin of Pinckney's, told MSNBC that a survivor of the shooting attack told her the gunman reloaded five times during the attack despite pleas for him to stop. “He just said, ‘I have to do it. You rape our women, and you're taking over our country,’” Johnson said. Police have not confirmed Johnson's statement.
Cornell William Brooks, the president and CEO of the National Association for the Advancement of Colored People, said Friday that the shooting was "unconscionable" and a "racial hate crime and must be confronted as such."
"We say this not because we’re trying to sow division but rather because we’re trying to sow unity — a unity of purpose, a unity of commitment, a unity of resolve so we can confront the racism in our midst," he said.
The Movement for Black Lives, a coalition of advocacy groups that includes Black Lives Matter and Ferguson Action, released a statement on Friday calling the attack "an undeniable act of terrorism" that was "intended to strike fear into the hearts of black communities."
President Barack Obama touched briefly on the case Friday while speaking at an annual meeting of the U.S. Conference of Mayors, saying that "racism remains a blight that we have to combat together."
State court records for Roof show a misdemeanor drug case from March that was pending against him and a misdemeanor trespassing charge from April. Authorities had no immediate details on those cases. It is not known whether Roof had previous cases against him as a juvenile, as juvenile records are usually sealed in South Carolina. Court records list no attorney for him.
Roof displayed a Confederate flag on his car plate, according to Kimberly Konzny, the mother of one of Roof's friends. His Facebook profile picture showed him wearing a jacket with patches of the flags of white-ruled Rhodesia (which became Zimbabwe in 1980) and apartheid-era South Africa.
In Montgomery, Alabama, the president of the Southern Poverty Law Center, Richard Cohen, said it is unclear whether Roof had any connection to any of the 19 white supremacist organizations the center has identified as operating in South Carolina.
But Cohen said that, on the basis of Roof's Facebook page, he appeared to be a “disaffected white supremacist.”
Al Jazeera and wire services. Philip J. Victor and David Douglas contributed to this report.