People for the Ethical Treatment of Animals filed the suit against NIH in 2021 on behalf of Madeline Krasno and Ryan Hartkopf, social media users whose comments had been removed from NIH posts. Krasno told The Washington Post in May that she witnessed animal abuse in a monkey research lab at the University of Wisconsin at Madison. She later began posting online about her experiences, only to find that both Wisconsin and NIH were removing her comments.