Republican presidential candidate Donald Trump slammed Google, Twitter and Facebook on Sunday (30 October), alleging that the companies are "burying" coverage of the FBI's re-opened investigation into Hillary Clinton's emails. The Republican presidential candidate, who has long accused the mainstream media of rigging the upcoming elections in favour of Democratic rival Hillary Clinton's by spreading "outright lies", took to Twitter to accuse the tech giants of being "dishonest media".

"Wow, Twitter, Google and Facebook are burying the FBI investigation of Clinton," Trump tweeted. "Very dishonest media!"

Although Trump does not mention the specifics of how the companies are allegedly burying the news or evidence to support his claims, he seems to be referring to Facebook and Twitter's 'trending' topics and Google's top stories.

On Friday, news broke that the FBI was reopening its investigation into Clinton's private emails after the agency discovered a trove of government-related emails on a laptop that longtime Clinton aide Huma Abedin used with her estranged husband, Anthony Weiner, that are "pertinent to the investigation".

Discovered during an unrelated sexting investigation, the new emails prompted a decision to reopen the probe into the use of Clinton's private email server during her tenure as secretary of state just 11 days before Election Day.

On Sunday, CNN host Brian Stelter and multiple media outlets pointed out that news of the FBI's renewed investigation was a trending topic on Twitter and the top story on Google News.

Earlier this year, Facebook denied allegations that editors running Facebook's trending news section were biased against conservative news outlets and stories. To improve its feature, the social media giant decided to rely on "a more algorithmically driven process" to determine what stories make it to the Trending box based on popularity and importance.

After fake news stories and conspiracy theories were erroneously being promoted by Facebook's Trending algorithm, the company got a "review team" to work on the feature, but exercise less editorial oversight than the previous news editors.

In response to Mashable's request for comment, a Facebook spokesperson also pointed the publication to the CNN tweet (embedded above).

Social media users were also quick to point out that Google, Facebook and Twitter are not "media companies".

This is not the first time Trump has claimed that Google has been suppressing negative news about Hillary Clinton during the campaign season.

During the summer, a conspiracy theory appeared in a viral video from online outlet SourceFed that claimed to show evidence that Google was actively altering search recommendations to hide negative coverage of Hillary Clinton. The theory was quickly debunked by news outlets as well as Google who pointed out that the search engine's 'autocomplete algorithm' filters out inaccurate information.

"Our autocomplete algorithm will not show a predicted query that is offensive or disparaging when displayed in conjunction with a person's name," a company spokeswoman told CNN at the time. "Google autocomplete does not favor any candidate or cause. Claims to the contrary simply misunderstand how autocomplete works."

Trump supported the unsubstantiated theory during a rally in Wisconsin in September saying:"The Google poll had us leading Hillary Clinton by two points nationwide, and that's despite the fact that Google search engine was suppressing the bad news about Hillary Clinton. How about that?"