Senate majority leader Chuck Schumer has demanded that Fox News “cease all dissemination of false white nationalist, far-right conspiracy theories” in a letter sent to the network’s leaders and owner Rupert Murdoch.

In the document, published by The New York Times on Tuesday, Schumer cites an alarming statistic measured by AP, indicating that “nearly one third of American adults believe that a group of people is trying to replace native-born Americans with immigrants for electoral gains.” Schumer also cites that viewers of Fox News are three times as likely to believe the theory, with marquee anchor Tucker Carlson having amplified it “in more than 400 episodes.”

“I urge you to take into consideration the very real impacts of the dangerous rhetoric being broadcast on your network on a nightly basis,” Schumer wrote. The senator also tied the network’s rhetoric to Saturday’s shooting in Buffalo, N.Y., in which a white 18-year-old white traveled hundreds of miles to the city and opened fire at a supermarket in a predominantly Black neighborhood, killing 10 individuals.

“In a manifesto posted online, the individual responsible for this heinous murder wrote that the shoppers there came from a culture that sought to ethnically replace my own people,” Schumer wrote.

The 180-page document by the shooting suspect that Schumer refers to touts a belief that immigrants and Black Americans are “replacers,” seeking to displace white individuals from the United States. While there is no evidence that the suspect derived his beliefs from cable news, Schumer’s letter urgently demands that Fox News evaluate its potential impact on viewers.

Representatives for Fox News declined to comment beyond pointing to Carlson’s statements from Monday evening’s broadcast, in which he called the shooter’s document “the product of a diseased and inorganized mind” and called for working toward a “colorblind meritocracy.”