In the week after the Stoneman Douglas High School shooting killed 17 people in Parkland, Florida, conspiracy theorists started spreading lies about it. They said that some of the surviving students giving media interviews had not, in fact, been present at the shooting. Instead, they were “crisis actors” brought in and paid to argue for gun control after the shooting.

One Florida legislator’s aide has already lost his job after emailing a reporter that two of the students “are not students here but actors that travel to various crisis [sic] when they happen.” But this theory’s baselessness, not to mention its tastelessness in the wake of a mass shooting, hasn’t stopped people from spreading it to discredit the students as they speak out about current gun laws.

On February 21, Princeton history professor Kevin M. Kruse took to Twitter to remind America that it had seen these types of tactics before. His viral tweet shared a 1957 clipping from the New York Times about the “Little Rock Nine,” a group of black students integrating an all-white high school in Arkansas.

In the article, the NAACP repudiated false stories that it said had been circulating about the students. These included “that the Negro children were being paid to attend classes at the newly integrated school,” and “that the children had been ‘imported’ from the North.”

As with the Parkland students, the assumption underlying these accusations against the Little Rock Nine was that someone was manipulating them— they couldn’t possibly have wanted to do what they were doing.

Raymond Arsenault, a civil rights historian and author of Freedom Riders, says that in 1960, white supremacists started to lean into this technique of discrediting student activists by linking their actions to Northern interference. That year, black students held sit-ins across the South.

“Part of the reaction among white supremacists and the mainstream media in the South was that somebody must be putting these kids up to this,” he says of the sit-ins. “There was the myth that blacks were content as long as outside agitators from the North didn’t get to them.”

As the Civil Rights Movement gained steam, white segregationists continued to make these claims about Freedom Riders, the activists who rode through the South in the early 1960s challenging segregation. White Southerners accused Northerners of orchestrating the Freedom Rides, both by sending their own people down to be Freedom Riders and by duping Southerners into joining their cause. But they also blamed another outside force—communism.

“There were two particular Freedom Riders who had been involved in an organization called F[air] Play for Cuba,” Arsenault says. Using this connection, newspapers in Alabama and Mississippi pushed the idea that Freedom Riders were communist insurgents.

White supremacists also pointed to a conspiracy after terrorists murdered Freedom Riders Andrew Goodman, Michael Schwerner, and James Chaney in 1964. When their bodies weren’t discovered for a month and a half, “the line from the white supremacists was that they had not been killed, they had just disappeared of their own volition, and the whole thing was a hoax,” Arsenault says.

But this wasn’t the only story. “The other more extreme version of it that many people believed, even after [the bodies] were discovered, was that the civil rights people killed them to make martyrs out of them,” he says. This line of thinking was applied to many other attacks, such as the 16th Street Baptist Church bombing that killed four young girls.

“People were programmed to believe this,” Arsenault says. “That all or most of the violence was being done by blacks themselves, or by white allies; that they were just trying to ruin the so-called southern way of life; and there’s nothing they wouldn’t do, including even killing their own if they needed to.”

Even if these tactics didn’t convince everyone that civil rights activists were murdering their own members for political reasons, it did create doubt that the Ku Klux Klan had been responsible for their deaths. “For a long while, there was an attempt to say the civil rights people were as bad as the Klan, that both sides were extremists who were upsetting the civic order,” he explains.

Today, Arsenault sees parallels between these false civil rights-era narratives and the current assertions surrounding the Parkland shooting. For conspiracy theorists who support looser gun regulations, “it’s really a matter of great importance for them to discredit [these students], just as it was to discredit the civil rights kids in the ‘60s.”

In his opinion, white supremacists’ slurs of civil rights activists “didn’t work;” in spite of them, students still registered voters and disrupted segregation. Regarding the current smear tactics toward Parkland students, he says, “I hope it won’t work again.”