The nature of his death has led to conspiracy theories that insist he was targeted by Democrats for leaking emails to WikiLeaks. The report quoted an unnamed federal investigator who claimed to have "seen and read the emails between Seth Rich and Wikileaks" and was heavily promoted on Fox.
US intelligence officials have since debunked that theory, stating that the emails were in fact stolen by Russian state-sponsored hackers in an attempt to "interfere with the USA election process".
"And they published, republished, and publicized the sham story-which they knew would be covered again and again, and republished, here and around the world-painting Joel and Mary's son as a criminal and a traitor to the United States", the lawsuit states.
"No parent should ever have to live through what we have been forced to endure", Joel and Mary Rich said in a statement released through their media representative. Another defendant, Malia Zimmerman, the reporter on the retracted Fox story, could not be immediately reached for comment.
Mr Butowsky, a wealthy Texas businessman sued by the Riches, told CNN on Tuesday night that he did not "understand this lawsuit at all".
It claims that Zimmerman and a regular Fox News guest, Ed Butowsky, intentionally fabricated a story that portrayed Rich as the person who leaked thousands of internal Democratic National Committee emails to WikiLeaks in 2016, which released them to the public in an act that proved damaging to Hillary Clinton's presidential campaign.More news: Cheltenham Day 2 tips: Samcro takes Ballymore Novices' Hurdle
The lawsuit claims that Joel and Mary are experiencing symptoms consistent with post-traumatic stress disorder, obsessive-compulsive behavior, and Mary is experiencing symptoms consistent with Social Anxiety Disorder.
Sean Hannity, who discussed the Rich murder on his show, told his audience that he would stop talking about the case "for now" after the story was retracted by Fox News "out of respect for the family's wishes", NBC News wrote.
Fox News' conduct has severely and "irreparably harmed" Rich's parents, the lawsuit argues, "because whatever opportunity that existed to investigate and find closure with regard to their son's murder was taken away from them". The suit contends that the reporters and the network "aided and abetted the intentional infliction of emotional distress" by the continued promotion of the story.
On May 16, 2017, nearly a year after Rich's death, Zimmerman published a story that seemed to bolster these theories, titled "Slain DNC Staffer Had Contact with WikiLeaks Say Multiple Sources".
The complaint says the Rich family is seeking monetary damages to be determined by a jury trial.