COLUMBIA, S.C. (CBSDFW.COM/AP) – The sister of the man on death row for killing nine people at a South Carolina church has been arrested at her school and charged with bringing pepper spray, a knife and marijuana onto the campus.

Morgan Roof was arrested Wednesday at A.C. Flora High School after a school administrator contacted the school resource officer, Richland County Sheriff Leon Lott said in a news release.

The 18-year-old is charged with two counts of carrying a weapon on school grounds and one count of simple possession of marijuana.

No one was hurt.

Mugshot of Dylann Roof’s sister, Morgan Roof. (credit: WLTX-TV)

A judge set her bond at $5,000 and said she could not return to the school. She was screened for a public defender. It was not known if she has an attorney yet.

Investigators say Roof also posted a Snapchat about the National School Walkout day protest against gun violence that alarmed fellow students, but no charges were filed for that message.

School principal Susan Childs posted a letter to parents on the school’s Twitter page explaining what occurred while students walked out to remember the 17 killed in the Parkland, Florida, Valentine’s Day school shooting.

“A student used social media to post a hateful message. The posting was not a threat, but was extremely inappropriate. That student was dealt with in a swift and severe manner as the posting caused quite a disruption,” Childs wrote.

South Carolina Gov. Henry McMaster issued a statement Wednesday night praising school administrators and the sheriff’s department, saying a “potential tragedy” was avoided at the school.

Dylann Roof (R), 21, listens to proceeding with assistant defense attorney William Maguire during a hearing at the Judicial Center July 16, 2015 in Charleston, South Carolina. Roof is charged with murdering nine worshippers at a historic black church in Charleston. (credit: Randall Hill – Pool/Getty Images)

Dylann Roof was convicted of fatally shooting nine African-American parishioners at Emanuel African Methodist Episcopal Church in 2015. A week before his sentencing early last year, Roof met with his family and told his sister he would invite her to his execution.

A video recording of one of the visits showed Roof’s sister trying to make small talk. Roof asked his sister what she wanted to do as a career, scoffing at the unoriginality of her dream to be a nurse. He told her that he no longer had to worry about making a living because he was in prison.

Roof’s sister smiled back. “You’re a professional dumbass,” she said.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)