A wealthy Trump supporter and a Fox News producer conspired to run a fake story about the death of a Democratic National Committee staffer while the White House looked on, a lawsuit has alleged.

Rod Wheeler, the detective cited in Fox News' controversial story about the fatal shooting of DNC staffer Seth Rich, has filed suit against the company for allegedly fabricating his quotes and pressuring him to push a false narrative.

“According to the complaint … Fox News was working with the Trump administration to disseminate fake news in order to distract the public from Russia's alleged attempts to influence our country's presidential election,” Mr Wheeler’s attorney, Douglas Wigdor, said in a statement.

Mr Wheeler was Fox News' prime source for a story claiming Mr Rich may have been murdered for releasing unflattering DNC emails to Wikileaks. According to the suit, however, Mr Wheeler never found evidence to support this.

Instead, Fox News producer Malia Zimmerman and prominent Trump donor Ed Butowsky pressured him to say so – even taking him to a meeting with then-White House Press Secretary Sean Spicer – in an effort to detract attention from the Russia investigation.

"Not to add any more pressure but the president just read the article,” Mr Butowsky allegedly texted Mr Wheeler shortly before the article was published. “He wants the article out immediately. It's now all up to you."

Jay Wallace, President of News at Fox News, called the allegation that Fox published the story to distract from the Russia investigation "completely erroneous".

“The accusation that FoxNews.com published Malia Zimmerman’s story to help detract from coverage of the Russia collusion issue is completely erroneous," he said. "The retraction of this story is still being investigated internally and we have no evidence that Rod Wheeler was misquoted by Zimmerman."

Mr Spicer told NPR he took the meeting as a favour to Mr Butowsky, and was not aware of any communication about it with the President. Mr Butowsky said he was joking about having the President’s ear.

Mr Wheeler, however, does not find it a laughing matter. The longtime Fox News contributor and former police detective says he was intially hired by Mr Butowsky to investigate Mr Rich’s death, on behalf of the 27-year-old’s grieving parents. The Rich family later disavowed both men and the Fox News report as a whole.

According to the suit, seen by The Independent, Mr Wheeler found little evidence to support any nefarious involvement by the DNC. Local police told him the shooting appeared to be a robbery gone wrong. The FBI told him they were not assisting local police in the investigation.

But Mr Butowksy, after meeting with journalist Seymour Hersh, told Mr Wheeler he had a source within the FBI who could confirm that Mr Rich had been in contact with WikiLeaks. (Mr Hersh has since dismissed these claims as “gossip”.)

In a 14 May voicemail, he told the detective the case had the “full attention of the White House”.

“Tomorrow, let’s close this deal, whatever we’ve got to do,” he said, according to the suit.

Two days later, Ms Zimmerman published a story claiming there was evidence that Mr Rich had communicated with WikiLeaks. The story cited Mr Wheeler and an unnamed FBI source.

According to the suit, the article contained several fabricated quotes from Mr Wheeler, including one in which he said: “My investigation shows someone within the DC government, Democratic National Committee or Clinton team is blocking the murder investigation from going forward.”

Mr Wallace said Fox News had "no evidence” that the quotes had been fabricated.

Less than a week after its publication, the story dissolved. The DC police, DNC officials, and even Mr Rich’s parents all denounced it as false. Mr Wheeler walked back his comments.

Fox News released a statement saying the article “was not initially subjected to the high degree of editorial scrutiny we require for all our reporting”.

The network then pulled the story from their website, but not before Mr Butowsky allegedly texted Mr Wheeler to scold him.

"One day you're going to win an award for having said those things you didn't say,” he said.