Two years before she was elected to Congress, Marjorie Taylor Greene hopped on Facebook to respond to a comment falsely claiming that the Parkland, Fla., school shooting was staged, according to screenshots posted by Media Matters for America, a liberal media watchdog group. Instead of rejecting the false claim surrounding the mass shooting that killed 17 people, Greene enthusiastically agreed with the conspiracy theory.

“Exactly!” she wrote in response.

Those comments, along with a number of other instances unearthed this week of Greene casting doubt on school shootings, sparked outrage among survivors and family members of those killed in two of the country’s deadliest mass shootings. By Thursday, several advocacy groups, including March for Our Lives-Parkland, Moms Demand Action, and Everytown for Gun Safety, called for Greene (R-Ga.) to give up her seat in the House of Representatives.

“She should resign,” Cameron Kasky, who co-founded the student-led group Never Again MSD after surviving Parkland, told The Washington Post. “She can apologize. I don’t think anybody will accept it.”

Greene’s office did not immediately respond to The Post’s request for comment as of early Friday. Facebook removed Greene’s comments for violating its policies following the watchdog group’s report, a Facebook spokesperson told The Post.

Greene, the first open supporter of the QAnon conspiracy theory to win a seat in Congress, has also continued to repeat former president Donald Trump’s baseless claims of mass election fraud. Earlier this week, Twitter temporarily suspended her account after she posted a clip with false claims about the election.

QAnon, a baseless conspiracy theory, is fueled by right-wing outrage online and in the real world. (Elyse Samuels/The Washington Post)

The Facebook conversations highlighted by Media Matters for America this week came nearly three years after 14 students and three staff members were killed in February 2018 when a former student at Marjory Stoneman Douglas High School opened fired on campus.

Three months later, Greene — who was then a right-wing media commentator — posted a news article about the Broward County sheriff’s deputy who failed to confront the shooter, Media Matters for America reported.

In the comments section, someone wrote: “It’s called a pay off to keep his mouth shut since it was a false flag planned shooting.” Greene replied: “Exactly!”

A month later, the watchdog reported, Greene had a similar interaction with another Facebook user after she posted a link to a piece published by the conspiracy theory-spreading site Gateway Pundit about former secretary of state Hillary Clinton.

One commenter called the Parkland shooting “fake,” adding that “none of the School shootings were real or done by the ones who were supposedly arrested for them.” The user spread other conspiracy theories and called the Sandy Hook massacre — in which 20 children and six staff members at an elementary school were fatally shot in 2012 — a “STAGGED [sic] SHOOTING.”

Greene liked the post and replied, “That’s all true.”

In December 2018, Media Matters for America reported, Greene claimed without evidence in a Facebook post that House Speaker Nancy Pelosi (D-Calif.) viewed school shootings as a convenient means of pushing for stricter gun laws.

“I am told that Nancy Pelosi tells Hillary Clinton several times a month that ‘we need another school shooting’ in order to persuade the public to want strict gun control,” Greene wrote.

The screenshots posted by the watchdog group led to harsh backlash this week.

Fred Guttenberg, the father of 14-year-old Jaime, who was killed in the Parkland shooting, took to Twitter to denounce Greene’s baseless claims.

“Your feelings on gun laws are irrelevant to your claim that Parkland never happened,” Guttenberg said in a tweet to the congresswoman on Thursday. “You are a fraud who must resign. Be prepared to meet me directly in person to explain your conspiracy theory, and soon.”

The Parkland chapter of March for Our Lives called Greene a “coward.”

“The shooting at our school was real. Real kids died and our community is still grieving today. You should be ashamed of yourself and resign from congress,” the organization tweeted. “Conspiracy theorists don’t deserve a seat in the people’s house.”

David Hogg, the activist and co-founder of March for Our Lives, vowed to organize against Greene if she did not apologize for the comments.

“I have one message for @RepMTG,” tweeted Hogg, a Parkland survivor. “Apologize Now or continue to spread the conspiracies and we will be sure to make the next two years of your life not only your last in Congress but a living hell as well.”