The sister of avowed white supremacist Dylann Roof, who was sentenced to die for the 2015 massacre at a historic South Carolina black church, was arrested for carrying weapons at a high school, according to police officials.
Morgan Roof, 18, was carrying a knife and pepper spray, as well as marijuana, at A.C. Flora High School in Columbia, South Carolina, on Wednesday, said Richland County Sheriff’s Department Lieutenant Curtis Wilson.
Roof, a student at the school, was charged with simple possession of marijuana and two counts of carrying weapons on school grounds.
“The school’s administrative staff acted appropriately by calling in the school resource officer (to) arrest Roof for violating school policy,” Wilson said in a statement. “No students were harmed as a result of this incident.”
The arrest came on the morning of a walkout by tens of thousands of students nationwide to demand stronger gun laws following last month’s Florida school shooting, in which 14 students and three faculty were killed.
WATCH: U.S. students leave class in mass walkouts across country to protest gun violence
Morgan Roof also startled authorities with a racially charged Snapchat post against the walkout, according to reports by the Post and Courier newspaper.
“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,” the newspaper quoted Roof as saying in the post.
Wilson said local news media received the screenshots of the Snapchat post, which “caused alarm to the student body,” but could not immediately confirm its contents.
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.
Roof was held in custody late on Wednesday and ordered not to return to the campus, local news media said.
On June 17, 2015, Dylann Roof sat for 40 minutes with parishioners at the landmark Emanuel African Methodist Episcopal Church in Charleston for a Bible study meeting before opening fire as they closed their eyes to pray.
He killed nine African-Americans in a hate-fueled attack he had been planning for months.
WATCH: Suspect identified in Charleston church shooting
He was sentenced to death after his conviction on 33 federal counts, including hate crimes and obstruction of religion. Roof was also sentenced in a separate state murder charge to nine consecutive life terms without parole and three consecutive 30-year prison terms for attempted murder.