Vandals spray-painted “KKK” and “White Supremacist” on the headstones of several high-ranking Civil War officials in a Raleigh, North Carolina cemetery last week, the latest in a series of similar stunts.

“Cowardly acts like this, under the cover of darkness, late at night, aren’t perpetrated by decent and thoughtful citizens,” Oakwood Cemetery Executive Director Robin Simonton said in a statement, according to the News & Observer.

“In these modern times, conversations on divisive issues should be held in person. Midnight assassinations don’t accomplish anything positive. Mature, non-emotional dialogue more often leads to agreement, or at least compromise.”

Simonton’s view on the controversial folks resting in Oakwood Cemetery is a big reason why she hosts coffeehouse chats on morality and sunrise yoga on the grounds – to discuss important and divisive issues like race and slavery through civil discourse.

But the thugs who doused monuments with red paint, spray painted anti-racist messages on headstones, and defaced other property causing an estimated $20,000 in damage apparently aren’t interested in civil discourse.

They’re the same type of people who repeatedly defaced the “Silent Sam” monument on the University of North Carolina-Chapel Hill campus in 2014 and 2014, and who tagged a Confederate Women’s Memorial at the Capitol with “Black Lives Matter” this summer, according to the News & Observer.

A total of nine monuments inside a section of Oakwood dedicated to Confederate Army soldiers were targeted in the attack, WNCN reports.

The culprits also hit a monument dedicated to former North Carolina Gov. Charles Aycock, who governed between 1901 and 1905.

The damage included “KKK” spray-painted on the marker for Randolph Abbott Shotwell, a sharpshooter in the Civil War, and “Not Heroes” painted on a bronze and granite marker dedicated to the crew of the Confederate submarine CSS H.L. Hunley, the News & Observer reports.

Gen. George B. Anderson’s grave was painted with “slavery” in large red letters, and red paint was splash up the towering monument. Gov. Aycock’s grave, one not from the Confederate era, was labeled “White Supremacist” with black paint.

Simonton and local historian Bruce Miller, who leads tours through the cemetery, worked to cover the graffiti with burlap and assess the damage over the weekend.

Raleigh police confirmed to WNCN that they’re investigating the incident, but would not discuss details.

Cemetery officials also declined to allow news crews to film the graffiti.

“The people who did this don’t deserve to have any more credence given to what they’ve done. And out of respect for the 25,000 folks that rest here, people come here for peaceful experiences and to celebrate life and the words on these monuments don’t do any of that,” Simonton told ABC 11.

She said officials are working with a specialty company to determine how to clean up the paint without further damaging the stone monuments.

“Some of these monuments are marble, and some of them are from 1870, so not only do we have to clean it up but we have to protect the stone so that it will stay here forever,” Simonton said.

The private, nonprofit cemetery is now soliciting donations to fix the damage, which is estimated to cost about $23,000, according to the news site.