A cache of emails revealed this week in which White House senior policy adviser Stephen Miller, in the run-up to the 2016 election, shared articles and websites affiliated with white nationalism has disturbed officials working in the Department of Homeland Security and Justice Department, who called the emails “sickening” and “proof” that Miller has been steering a racist immigration policy under President Trump.

The emails sent from Miller to editors of the far-right website Breitbart and obtained by the Southern Poverty Law Center show Miller sharing a story from the white nationalist site VDare, pushing for Breitbart to write about a novel popular among white nationalists, and linking to a report detailing second-generation Muslims with the subject line “Huge Surge in US newborns named 'Mohammed.’”

The civil rights nonprofit said that after reviewing 900 emails, it was “unable to find any examples of Miller writing sympathetically or even in neutral tones about any person who is nonwhite or foreign-born.” In one such email chain, the SPLC said Miller directed Breitbart reporter Katie McHugh, who supplied the emails to the group, to aggregate information from American Renaissance, a white supremacist journal, for a story on crimes committed by nonwhite people.

“It’s sickening to know that someone with these viewpoints held a position of trust for a United States Senator," said one DHS official, referring to former senator and attorney general Jeff Sessions, "and now in the White House. Not that it wasn’t clear before — these emails just confirm what we all know. I’m disgusted that my venerable agency has turned into his personal tool for hate.”

BuzzFeed News spoke with nine DHS and DOJ officials for this story, all of whom requested anonymity because they were not authorized to speak on the matter.

Miller’s influence in shaping a hardline immigration policy, including overhauling and restricting asylum to those seeking protection, is well known. Under the Trump administration, DHS has attempted to ban people from several Muslim-majority countries, bar asylum for those who traveled through Mexico or crossed the border without authorization, and force immigrants seeking protection to remain in Mexico for months while their cases proceed. At the same time, Trump has cut refugee levels to historically low numbers.

“Different people and different administrations can have different attitudes toward immigration, but to have someone with a vendetta against immigrants, and nonwhite immigrants in particular, in charge of this administration’s immigration agenda is beyond the pale,” said a DHS official.

A senior DHS official speaking about the emails said that “if true, he needs to go” and that regardless, “he should probably step down because his politics have become a distraction.”