Image copyright LinkedIn Image caption Fox News sued over conspiracy theory following death of Seth Rich

The parents of a Democratic party employee who was shot and killed in 2016 are suing Fox News for spreading a conspiracy about his death.

After their son Seth Rich died, the cable network made an unsubstantiated link between his death and Wikileaks' disclosure of hacked DNC emails.

Joel and Mary Rich have filed a lawsuit that says Fox News "intentionally exploited" their son's murder.

The 16 May 2017 Fox story was retracted by the network after a week.

A Fox News spokesperson said: "We can't comment on this pending litigation."

The lawsuit says Fox News investigative reporter Malia Zimmerman and Fox News guest Ed Butowsky spread "false and fabricated facts" that caused emotional harm.

Mr and Ms Rich said in a statement: "No parent should ever have to live through what we have been forced to endure", according to US media.

"The pain and anguish that comes from seeing your murdered son's life and legacy treated as a mere political football is beyond comprehension," they said.

The lawsuit adds: "Fox continued to exploit the sham story because it was good for ratings."

Seth Rich, a 27-year-old Nebraksa college graduate and DNC staffer, had lived in Washington DC from 2012 until his death on 10 July 2016.

He was shot in the back in the north-west of the city at the Bloomingdale neighbourhood, where residents had reported a spate of gunpoint robberies.

Image copyright Courtesy of the Rich family Image caption The 27-year-old was shot dead in in Washington, DC, last year

Following his death, some right-wing media suggested his killing was revenge by figures linked to the Hillary Clinton campaign for allegedly leaking embarrassing DNC emails to Wikileaks.

Sean Hannity, writers at InfoWars, and Republicans in Congress contributed to spreading the conspiracy theory.

Prominent Republican Newt Gingrich took up the story after it was published and said on Fox News: "It wasn't the Russians [who hacked the DNC's emails].

"It was this young guy who was disgusted by the corruption of the DNC."

Mr and Ms Rich argue in the lawsuit that Fox News' reaction to his death painted their son "as a criminal and traitor to the United States".

Wikileaks itself fuelled the conspiracy theory by offering a reward for the capture of Mr Rich's killer and hinting that he may have been the source of the emails.

No evidence has emerged to indicate that Mr Rich provided the emails to the anti-secrecy organisation.

The Washington Metropolitan Police Department said his murder was part of an armed robbery.

The lawsuit, filed in the Federal District Court of Manhattan, claims Fox spread the false story "through lies, misrepresentations, and half-truths - with disregard for the obvious harm that their actions would cause Joel and Mary".

Mr Butowsky, a wealthy Texas businessman sued by the Riches, told CNN on Tuesday night that he did not "understand this lawsuit at all".

"This whole thing has caused unbelievable damage to my life and my family," he said.

"And the idea that somebody has capitalised is ridiculous. It just doesn't make any sense to me."