CNN’s reporting on the Trump-Russia dossier has left out at least one crucial fact: the close ties between the network and the opposition research firm at the center of the dossier controversy.

CNN’s reporting on the dossier, led by justice correspondent Evan Perez, has been favorable to the firm, Fusion GPS, and hyped the dossier’s credibility. Left out of Perez’s reporting, which has relied largely on unnamed sources, is his personal closeness to Fusion GPS’ operatives. Fusion has repeatedly been described in Senate testimonies as a smear-for-hire operation that manufactures misleading or false media narratives for its clients.

Glenn Simpson, the Fusion co-founder most often associated with the dossier, is used to working on stories with Perez. As reporters at The Wall Street Journal, Perez and Simpson regularly co-authored stories on national security.

Another Fusion founder, Tom Catan, worked as a reporter for the Journal at the same time as Perez and Simpson. The third Fusion co-founder, Peter Fritsch, worked above Perez and Simpson as the senior national security editor.

Simpson and Fritsch left the WSJ in 2011 to launch Fusion. Perez jumped from the paper to CNN in 2013. Another longtime Journal reporter, Neil King, left the paper to join Fusion in December 2016.

Photos posted to Facebook underscore the personal closeness between Perez and the Fusion GPS operatives. One photo posted by Perez shows King, who left the Journal for Fusion in December 2016, and another man posing for a picture at The Bullpen, an outdoor bar right outside of the Washington Nationals’ stadium.

The Bullpen is a popular fan destination before baseball games. King is shown wearing a shirt with the Nationals name and logo across the front. The photo was posted in August 2016, four months before King joined Fusion GPS.

Another photo, from September 2015, shows Perez, King and Fusion co-founder Peter Fritsch.

In 2011, the same year that Fritsch co-founded Fusion, Perez posted two photos on Facebook from an apparent fishing trip with Fritsch. The photos show the Wall Street Journal alum holding a fishing rod and standing ankle-deep in a lake. In one of the photos, Fritsch can be seen flipping the camera his middle finger.

At no point in Perez’s reporting did he disclose his close ties to the Fusion GPS operatives.

The Wall Street Journal’s editorial board sounded the alarm about its former reporters in a remarkable editorial earlier this month, accusing Beltway media of being complicit in a coverup with Fusion. “Americans don’t need a Justice Department coverup abetted by Glenn Simpson’s media buddies,” the editors wrote in a scathing takedown of the firm.

Simpson’s wife, Mary Jacoby, bragged about his role in the dossier in a lengthy June 2017 Facebook post reviewed by The Daily Caller.

Jacoby claimed that “some people still don’t realize what Glenn’s role was in exposing Putin’s control of Donald Trump,” referencing the dossier’s thesis. The dossier claimed that Russians had evidence of damaging information on Trump that they would use to blackmail him, an explosive accusation for which there remains no public evidence.

CNN’s coverage of the dossier has been relatively soft. CNN anchor Jake Tapper, usually known for his aggressive coverage, gave Fusion a pass while reporting on the story Wednesday evening.

“Certainly some of the more lurid charges in that dossier remain uncorroborated, but some of the details have been proven accurate,” Tapper said. But the newsman failed to mention reporting he did back in January that called the dossier’s credibility into question.

On Jan. 10, the day that BuzzFeed published the dossier, Tapper cited a government source who told him that a key claim in the dossier about Trump’s lawyer, Michael Cohen, was false. The dossier alleged that Cohen traveled to Prague last August to meet with Kremlin operatives. But Tapper reported that government officials believed that a different Michael Cohen had actually traveled to the Czech Republic. Tapper has not acknowledge that reporting since that initial segment. (RELATED: Jake Tapper’s Dodgy Dossier Reporting)

CNN’s reporting on the dossier has similarly muddied the waters with incorrect information on multiple other occasions.

CNN did not respond to The Daily Caller’s request for comment about Perez’s ties to Fusion’s partners.

Fusion GPS, currently at the center of the Russia investigation, has a reputation for working misinformation into the media for political clients.

Thor Halvorssen, founder of the Human Rights Foundation, described Fusion GPS as “highly paid smear experts” in written testimony to the Senate Judiciary Committee. He says that the firm went after him several years ago because he criticized a corrupt Venezuelan company Derwick Associates that counted Fusion as a client.

Alek Boyd, a former associate of Halvorssen’s, says he was also targeted in a similar smear campaign because he drew attention to Derwick’s alleged financial misdeeds. He said he also faced false allegations of being a pedophile, sexual deviant and drug addict.

“Fusion is basically a pen-for-hire shop, whose owners are prepared to concoct completely spurious stories that are fed to media contacts developed over years of legitimate work in reputable outlets,” Boyd told TheDC.

Bill Browder, a renowned human rights activist and top Putin enemy, offered similar testimony before the committee.

Browder described how Russian lawyer Natalia Veselnitskaya, the same attorney that met with Donald Trump Jr. last year, used Fusion GPS to conduct a smear campaign against him.

“Veselnitskaya, through Baker Hostetler, hired Glenn Simpson of the firm Fusion GPS to conduct a smear campaign against me and Sergei Magnitsky in advance of congressional hearings on the Global Magnitsky Act,” Browder stated in his written testimony.

“He contacted a number of major newspapers and other publications to spread false information that Sergei Magnitsky was not murdered, was not a whistle-blower, and was instead a criminal. They also spread false information that my presentations to lawmakers around the world were untrue,” Browder said.

Browder’s testimony drew bipartisan praise, with California Sen. Dianne Feinstein, the ranking Democrat on the Senate Judiciary Committee, praising Browder’s account as “some of the best testimony I’ve ever heard.”

CNN has faced scrutiny in the past for its reporting on the Russia probe. Two prominent CNN reporters and an editor were forced to leave the network after repeated mistakes in covering the Russia probe, including one report that CNN retracted entirely. (RELATED: CNN’s Wolf Blitzer Humiliates Colleague Over Quality Of Her Sources)

WATCH: CLINTON TIES TO FUSION GPS

This article has been updated to include Tapper’s full quote, in which he neglected to mention his previous reporting calling the dossier’s credibility into question.