The 18-year-old sister of Charleston, S.C., church shooter Dylann Roof was arrested Wednesday for carrying pepper spray, a knife and marijuana in her high school, authorities said.

Morgan Roof also posted on Snapchat a critique of Wednesday’s National Student Walkout protest against gun violence, the Post and Courier of Charleston, S.C., reported.

“Your [sic] walking out for the allowed time of 17min, They are letting you do this, nothing is going to change what (the expletive) 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,” Roof posted, Fox 57 reported.

“I hope it’s a trap and y’all get shot.”

– Comment on Morgan Roof’s Snapchat account

No students were harmed in connection with the arrest, Fox 57 reported.

FILE - In this June 18, 2015, file photo, Charleston, S.C., shooting suspect Dylann Storm Roof is escorted from the Cleveland County Courthouse in Shelby, N.C.   Solicitor Scarlett Wilson told The Associated Press on Friday, March 31, 2017,  that Roof is scheduled to enter a guilty plea during a hearing on April 10 in Charleston. The plea on all of his state charges, including nine counts of murder, comes in exchange for a sentence of life in prison, the prosecutor said. Roof has been awaiting trial on state murder charges for the deaths of nine black parishioners at Charleston's Emanuel AME Church in June 2015. (AP Photo/Chuck Burton, File)

Dylann Roof has been convicted in connection with the 2015 shooting deaths of nine churchgoers in Charleston, S.C.

 (Associated Press)

Roof was transported to the Alvin S. Glenn Detention Center, the station reported. A $5,000 bond carried a judge’s condition that Roof not return to A.C. Flora High School, the station reported.

The school’s principal sent a letter to parents, informing them about the incident, the station reported.

Roof’s brother, Dylann Roof, was convicted on federal charges in 2016 and pleaded guilty to state charges in 2017 in connection with the June 2015 murders of nine African-American churchgoers at Emanuel AME Church in Charleston.