The sister of avowed white supremacist Dylann Roof, who was sentenced to die for the 2015 massacre at a historic South Carolina black church, has been arrested for carrying weapons at a high school.
Morgan Roof, 18, was carrying a knife and pepper spray, as well as marijuana, at a school in Columbia, the Post and Courier and other media reported.
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The arrest came on the morning of a protest walkout by thousands of students nationwide to demand gun law reform following a Florida mass shooting that killed 14 students and three teachers a month ago.
Morgan Roof also alarmed authorities with a racially charged Snapchat post against the walkout, saying in part, "I hope it's a trap and y'all get shot", the newspaper and other media said.
In response, South Carolina Governor Henry McMaster called for more security at schools.
"For months, I have called on the general assembly to join me in placing a trained, certified police officer in every school," he said in a statement.
She was held in custody late on Wednesday on a bond of $US5000 (NZ$800) and ordered not to return to the campus, media said.