The U.S. district judge presiding over the federal case against Luigi Mangione, the man accused of murdering UnitedHealthcare’s CEO on a Midtown Manhattan street last year, said Department of Justice officials may have violated court rules with inappropriate social media posts and threatened sanctions. 

“It appears,” Judge Margaret Garnet wrote in an order published on Wednesday, “that multiple employees at the Department of Justice may have violated Criminal Rule 23.1 and this court’s order of April 25, 2025..” 

The federal rule, as applied in the Southern District of New York, where Mr. Mangione was indicted, refers to public statements attorneys and prosecutors, and their staff, can make in criminal cases about defendants, who have yet to be convicted or acquitted, to ensure their right to a fair trial. 

In a letter filed on Monday, defense attorneys for the alleged killer told the judge that the “government has continued to prejudice his right to a fair trial in a death penalty case in violation of his Fifth and Eighth Amendment rights.” 

Mr. Mangione, 27, faces 20 charges in three separate jurisdictions for the same crime, the shooting of the CEO, Brian Thompson, a father of two, in front of the Hilton hotel last December. Video surveillance shows a masked man in a hooded sweatshirt approaching Thompson from behind and firing several shots from what police say was a 3-D printed ghost gun. The executive was pronounced dead at the hospital half an hour later, while the suspect fled the scene on a bicycle. 

After an extensive manhunt, Mr. Mangione was arrested at an Altoona, Pennsylvania, McDonald’s, and eventually extradited to New York. He is being held at the notorious Metropolitan Detention Center in Brooklyn, and faces gun possession and other charges in Pennsylvania, murder charges in New York state court, as well as death penalty-eligible murder charges in federal court. 

On April 1, two weeks before a grand jury indicted him, Attorney General Pam Bondi publicly declared that the Department of Justice was going to seek the death penalty in the high-profile case. 

President Trump, who presided over an execution spree in the final weeks of his first term and ferociously denounced President Biden’s decision to commute the death sentences of all but three condemned federal convicts, signed an executive order early in his second term committing to seek and carry out death sentences for federal crimes.

During Mr. Mangione’s court appearance on April 25, defense attorneys argued that their client is innocent until proven guilty and that public comments — like Ms. Bondi’s — asserting his guilt would prejudice the jury pool. The district judge ordered both parties to adhere to the court’s rules and refrain from making public statements about the defendant’s possible guilt. But according to the defense’s recent letter, the government violated that order.  

“On September 18, 2025, the President of the United States appeared on Fox News Channel and stated that Mr. Mangione ‘shot someone in the back as clear as you’re looking at me…he shot him right in the middle of the back – instantly dead,’” the defense wrote, referring to a segment during which Mr. Trump told a “Fox News Sunday” anchor, Shannon Bream, that he believed “girls” who are “going crazy” for Mr. Mangione are suffering from a “sickness” that needs to be “investigated.”  

The president’s comments, and his astonishment that people would admire and celebrate an alleged killer, were not the problem. The defense took issue with the fact that the Fox News clip was retweeted by the deputy director of the Department of Justice Office of Public Affairs, Chad Gilmartin, who captioned the since-deleted post with “@POTUS is absolutely right,” according to the screenshot submitted by the defense team. 

Mr. Gilmartin’s post was then reposted by Brian Nieves, the chief of staff to Deputy Attorney General Todd Blanche. 

The defense also pointed to the White House press secretary, Karoline Leavitt, who referred to Mr. Mangione as a “left-wing assassin” in a September 22 news conference, comparing him to another alleged assassin, the man charged with murdering Charlie Kirk. Later that day, the White House announced in a press release that it would classify the self-proclaimed “left-wing anti-fascist” group Antifa as a “domestic terrorist organization,” in its aim to address the “Radical Left violence that has permeated the nation in recent years.” 

But Mr. Mangione’s defense attorneys wrote that their client was not associated with any left-wing extremist groups, let alone the alleged assassin of Charlie Kirk.  

“The Government has indelibly prejudiced Mr. Mangione by baselessly linking him to unrelated violent events, and left-wing extremist groups, despite there being no connection or affiliation,” defense attorneys wrote in their letter. 

“A recent, tragic, high-profile murder has only increased this prejudicial rhetoric. The attempts to connect Mr. Mangione with these incidents and paint him as a ‘left wing’ violent extremist are false, prejudicial. … Mr. Mangione in fact does not support these violent actions, does not condone past or future political violence, nor is he in any way aligned with the group mentioned in the White House press release.” 

In her order, the presiding judge asked prosecutors to explain these statements and to advise Mr. Blanche that “future violations may result in sanctions, which could include personal financial penalties, contempt of court findings, or relief specific to the prosecution of this matter.” She further reminded the government that these rules also apply to Ms. Bondi.  

Judge Garnet told prosecutors that they could include their response to her order in their reply brief to the death penalty motion, which was filed by the defense team last Saturday.   

In that 114-page filing, the defense asked the judge to block the death penalty-eligible charge, murder through the use of a firearm, because a “torrent of prejudice from multiple public officials” violated their client’s constitutional rights and made it impossible for him to receive a fair trial. 

Defense attorneys wrote that Mr. Mangione had effectively been portrayed by state and government officials as a “captured cartel chief or comic book villain.” 

When Mr. Mangione was extradited to New York, 10 days after his arrest in Pennsylvania, he arrived in chains and a bright orange prison jumpsuit at Manhattan’s Wall Street heliport, and was met by Mayor Eric Adams and the New York Police Department commissioner, Jessica Tisch, other high ranking officials, and a swarm of NYPD officers. The lead defense attorney, Karen Friedman Agnifilo, argued that this perp-walk was staged for the “political needs of federal and local officials and not for public safety.” 

“In a show of force befitting a captured cartel chief or comic book villain, Mr. Mangione … who had never been in trouble with the law, was ‘perp walked’ before scores of television cameras and press reporters, surrounded by armed law enforcement officials in tactical SWAT gear and raid jackets,” Ms. Agnifilo wrote. 

She added, “Potential jurors … were imprinted with a scene out of a Marvel movie, with dozens of agents needed to protect the public from the shackled monster Mangione.” 

Federal prosecutors have yet to respond to the motion. 

Mr. Mangione’s next appearance in federal court is scheduled for December 5. He is also set to appear in state court on December 1. It is unclear which of the two cases will go to trial first.