(CN) - The sister of the man sentenced to death for killing nine black parishioners in the basement of a Charleston, S.C., church in 2015 was arrested Wednesday on charges of carrying a weapon onto school property and marijuana possession.
In a tweet, South Carolina Governor Henry McMaster said a "potential tragedy was avoided at AC Flora High School."
The governor went on to laud both students and educators for reacting quickly and reporting "suspicious activity and and behavior to their Richland County Sheriff's Department school resource officer."
Officials with the Richland County Sheriff's Department said high school student Morgan Roof was arrested for violating school policy after administrators at the school informed a school resource officer that she was in possession of knives, pepper spray and marijuana.
Roof, 18, allegedly posted a video on Snapchat saying she hoped students participating in Wednesday's National Walkout Day, a nationwide series of protests against gun violence, would "get shot," and suggested that only "black people" would be taking part in the rallies.
"Your walking out for the allowed time of 17min, they are letting you do this, nothing is gonna change what tf you think it's gonna do? I hope it's a trap and y'all get shot we know it's fixing to be nothing but black people walkin out anyway. No offense ofc buuut," she posted.
Her brother, Dylann Roof, gunned down nine black churchgoers attending a Bible study at the Emanuel AME Church in downtown Charleston in June 2015.
He is now awaiting execution by lethal injection at the federal prison in Terre Haute, Indiana.
Following her arrest Morgan Roof was taken to the Richland County Detention Center where she was held on $5,000 bond.
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