A left-leaning advocacy group is putting pressure on the U.S. Department of the Treasury to investigate whether the agency violated federal law in its interaction with conservative media outlets.

Last month, advocacy group Democracy Forward released emails between Treasury officials and Fox Business Network employees after obtaining the messages through a Freedom of Information Act (FOIA) request. The emails underscored the often cozy relationship that exists between Fox News or Fox Business and the Trump administration.

On Tuesday, in a new letter exclusively shared with The Daily Beast, Democracy Forward called upon on the Treasury’s inspector general to look into whether some of the actions unearthed in that FOIA deep-dive violated a relatively obscure federal law prohibiting government agencies from spreading information without disclosing its origin.

In a specific instance cited by Democracy Forward, a Treasury communications official directed a Fox Business Network employee to make changes to an article about a trip taken by Treasury Sec. Steve Mnuchin. The official crafted specific alterations for the article and Fox staff acquiesced to the official’s preferred headline and article text wording.

While lobbying for changes in a news article is common for flacks at both government agencies and private companies, Democracy Forward argued that the emails show Treasury officials “exerting substantial influence over FBN’s coverage and raises troubling questions regarding Treasury officials’ compliance with the covert propaganda ban.”

“This extremely close coordination between Treasury officials and Fox News suggests that the Trump administration may be violating federal law that prohibits government-sponsored propaganda,” Democracy Forward’s press secretary Charisma Troiano said in a statement. “This kind of cozy, behind-the-scenes interaction between government employees and members of the media raises alarm bells, and such direct intervention could be illegal.”

The group also announced Tuesday that it will attempt to see if other agencies have similarly influenced coverage at right-wing outlets behind the scenes.

Democracy Forward will file FOIA suits against the Department of Justice, and Health and Human Services, among others, in order to review correspondence between officials and right-leaning media outlets including Fox News, Breitbart, The Daily Caller, The Daily Wire, NewsMax, and One America News Network.

Democracy Forward isn’t the first advocacy group to focus on exposing the close links between Fox News and various arms of the Trump administration. Last year, The Daily Beast reported on the cozy relationship between Fox News and the Environmental Protection Agency via emails obtained through FOIA requests by the Sierra Club. Obtained correspondence showed Fox & Friends production staff allowing an EPA official to review a segment script prior to an on-air interview with the agency’s then-administrator Scott Pruitt.