WikiLeaks - which is now seen by many US Democrats as a vehicle for Russian intelligence - retweeted stories containing the latest claims, which many interpreted as confirmation. WikiLeaks founder Julian Assange last year appeared to suggest Rich was the leaker.
US authorities have accused Russian operatives of being the source of the leaks.
The Fox News story was also shared by the Russian Embassy in the UK on Twitter, receiving thousands of shares. But the report has since been proven to be inaccurate. Wheeler said he had no information to that effect, and an FBI spokesman told the media that, contrary to the report, it had not conducted a forensic analysis of Rich's laptop that showed he had been in contact WikiLeaks.
A spokesman for the Rich Family, Brad Bauman, lashed out at those who continue to promote the story, which includes prominent Fox News anchor Sean Hannity.
"Anyone who continues to push this fake news story after it was so thoroughly debunked is proving to the world they have a transparent political agenda or are a sociopath," he told CNN. "It either case, they should be taken off the air because they are either blind to the damage they are doing to a murder victims family or don't care, showing a profound lack of judgment and common decency."
On Sunday, speculation that the young DNC staffer was involved in the leaks was promoted by internet millionaire and the embattled founder of Megaupload, Kim Dotcom. Dotcom tweeted that Rich was the leaker and that he himself was also involved, promising to issue a statement after meeting with his lawyers this week.
Social media has been full of people promoting the notion of a cover-up.
Things got weirder still after internet sleuths uncovered what appeared to be Rich's social media accounts, including his Reddit username, "MeGrimlock4" and Twitter handle, "@panda4progress".
His online persona revealed Rich was a huge supporter of Sanders, which conspiracy theorists hold up as evidence of his motive to leak the e-mails which showed the DNC colluded to prevent Sanders from gaining the party nomination.
In a strange development, users discovered a tweet by former DNC director of data science Andrew Therriault, which appeared to posthumously mock Rich, referring to him as an "embarrassment".
On 27 April, quoting a tweet which read, "TIL: A group of Pandas is called an 'Embarrassment' #pandafacts", Therriault tweeted: "cc: @panda4progress". The tweet has since been deleted.
Not long after, Reddit appeared to alter posts made by Rich - a big no-no from the perspective of the site's users - to remove a comment in which he shared his e-mail address, linking him to the account.
Reddit has a strict policy against sharing personal information, but a previous case in which Reddit chief executive Steve Huffman manually altered user's comments drew ire from users and forced a public apology.
At the time, even former CEO Ellen Pao weighed in, saying she "would have immediately fired anyone" who did what Huffman did.
News.com.au contacted Reddit to ask about the alleged changes made to Rich's comment history.
Meanwhile, The Washington Post has published multiple reports this weekend describing claims of a cover-up over the murder of Seth Rich as fake news.
"The re-emergence of the conspiracy theory this week, which did not lack for real news, revealed plenty about the fake news ecosystem ... in the Trump era," the paper wrote. "It also happened to cause untold pain for the Rich family, which has sent a cease-and-desist letter to the so-called private investigator who led this dive back into the fever swamp."
