Morgan Roof had also made a social media post on Snapchat which alarmed the student body.
In it, Morgan Roof said she hoped the students participating in the National Walkout Day, protesting gun violence, would "get shot."
Students across the U.S. participated in the walkout, including many at schools in the Midlands and Columbia. AC Flora was one of the participating schools.
Based on what Morgan Roof posted online, she disagreed with the walkout. What struck a nerve was her comment that "we know it's fixing to be nothing but black people walkin out anyway."
After her brother murdered nine black people at a church which he purposely selected because of its black parishioners, he told FBI agents he was hoping to start a race war.
"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," Morgan Roof posted.
On the weapons and drug possession charges, a school resource officer was contacted by a school administrator, in reference to Morgan Roof being in possession of marijuana, pepper spray, and a knife, according to the sheriff's department.
No students were harmed as a result of this incident, the sheriff's department said.
Roof was taken to the Alvin S. Glenn Detention Center.
Richland County Sheriff Leon Lott said the school’s administrative staff acted appropriately by calling in the SRO to arrest Morgan Roof for violating school policy.
"Potential tragedy was avoided at AC Flora High School," S.C. Gov. Henry McMaster said in a news release. "We owe a debt of gratitude to all involved who acted so quickly and decisively."
Dylann Roof, a self-avowed white supremacist, killed nine black parishioners in June 2015 during a bible study session at Charleston's historic Mother Emanuel AME Church.
Roof pleaded guilty to nine counts of murder and three counts of attempted murder. He is on death row in Indiana.
