Fox News said it had retracted a story about the murder of Seth Rich, a former Democratic National Committee staffer who was killed in Washington, D.C. last July and which has provided fodder for Sean Hannity, the network’s longest-serving primetime host. Hannity has in recent days promoted a debunked theory that Rich was killed in exchange for providing internal documents to Wikileaks, prompting statements of outrage from his family.

“On May 16, a story was posted on the Fox News website on the investigation into the 2016 murder of DNC Staffer Seth Rich. The article was not initially subjected to the high degree of editorial scrutiny we require for all our reporting. Upon appropriate review, the article was found not to meet those standards and has since been removed,” the network said in a posting online Tuesday. “We will continue to investigate this story and will provide updates as warranted. ”

The retraction is believed to be one of the first made of a Fox News story. A retraction is relatively unheard of at the 21st Century Fox-owned outlet.

Right-wing outlets including Breitbart and The Drudge Report have suggested with items and links that Rich could have been killed in retribution for the leak of DNC emails during last year’s presidential campaign, an act that has largely been attributed to Russian interference. The theory about Rich’s murder has yet to be proven.

Fox News lent the story new momentum last week when it posted an item about the story after Rod Wheeler, a Fox News contributor who is also a private investigator Rich’s family has hired, was shown on Fox affiliate WTTG suggesting he had evidence linking Rich to Wikileaks. Subsequently, Wheeler told CNN he had no evidence.

Theories around Rich have helped fill recent segments on “Hannity,” Fox News 10 p.m. primetime mainstay. It could not be learned if Hannity was planning to discuss the new development and Fox News’ retraction on his show this evening.