Luigi Mangione, the 26-year-old accused of killing UnitedHealthcare CEO Brian Thompson, is expected to appear in federal court on Friday to enter a plea on charges of stalking and murder.

The court appearance comes about a week after a federal grand jury indicted Mangione on four federal charges in the December 4 killing of the insurance executive.

The targeted shooting of Thompson, who was on his way to a UnitedHealthcare investors’ conference in New York, has led to an outpouring of support for Mangione from people with deep frustration and anger at the American for-profit health care system.

Mangione’s last court appearance in February drew a sizable contingent of supporters, many of whom wore green in solidarity – a reference to Nintendo’s “Luigi” character – and stood outside holding signs reading “Free Luigi” and “Health care is a human right.”

Mangione’s top federal charge, murder through use of a firearm, could land him a death sentence or life in prison, according to the US Attorney’s Office for the Southern District of New York.

The Justice Department filed a notice on Thursday saying it intends to seek the death penalty, weeks after Attorney General Pam Bondi directed the office to seek the punishment.

He also faces state charges in New York and Pennsylvania related to the shooting and ensuing weeklong manhunt.

In New York, he has pleaded not guilty to state murder and terror charges. In his Pennsylvania case, he faces firearm and forgery charges in connection to the 3D-printed firearm and false identification allegedly in his possession when he was arrested at a McDonald’s in Altoona.

He did not enter a plea in Pennsylvania before he was extradited back to New York to face charges there.

An attorney for Mangione filed a series of motions in Pennsylvania state court seeking to dismiss the charges against him and suppress several pieces of evidence should the case go to trial.

His lawyers said Mangione was illegally stopped and searched by authorities and requested that Mangione’s recovered writings not be referred to as a manifesto.

The charges stem from the December 4 shooting of Thompson in Midtown Manhattan that set off a five-day manhunt.

Mangione was arrested in connection with the killing in Pennsylvania, more than 270 miles away from the shooting.

He allegedly possessed on him the fake ID used by the suspect, the gun they believe was used in the shooting and a handwritten “claim of responsibility,” authorities have said.

Mangione was not insured by UnitedHealthcare, but at the time of his arrest, he allegedly had a handwritten notebook that expressed “hostility toward the health insurance industry and wealthy executives in particular,” according to a federal complaint.

Notably, three 9mm shell casings from the crime scene had the words “delay,” “deny” and “depose” written on them, the NYPD has said, an apparent nod to a 2010 book critiquing insurance industry tactics.

Mangione has garnered support from some who see the American health insurance industry as broken, overly expensive and quick to deny coverage.

The majority of insured US adults had at least one issue with their health insurance within the span of a year, including denial of claims, according to a survey released in June 2023 by nonprofit health policy research group KFF.

As of April 24, a legal defense fund in support of Mangione has raised more than $900,000.

“To be honest, I’m really not that surprised that all this widespread support has sort of risen up in this moment for this young man alleged to have taken action in this way,” Sam Beard, spokesperson for the December 4th Legal Committee – the group fundraising for Mangione – previously told CNN’s Laura Coates.

“I think Americans are fed up with the way of the – that the health insurance system operates,” Beard added.

Meanwhile, mainstream politicians have lambasted Mangione’s alleged actions as horrific crimes and said he should face serious consequences.

“In America, we do not kill people in cold blood to resolve policy differences or express a viewpoint,” Pennsylvania Governor Josh Shapiro said the same day Mangione was apprehended. “He is no hero.”

High public interest in Mangione

The sharply polarising views on his case have made Mangione a particular focus of public attention.

In December, Mangione was whisked from Pennsylvania to downtown New York on a jet and a helicopter in a remarkable spectacle in front of media cameras.

Once in New York, a handcuffed Mangione was led on a lengthy “perp walk” by a swarm of heavily armed NYPD officers, with New York Mayor Eric Adams and NYPD commissioner Jessica Tisch right behind them.

The defense has accused law enforcement and prosecutors of inappropriately playing to the television cameras in that incident.

Mangione’s February 21 court hearing in New York on state charges drew dozens of his supporters despite frigid temperatures and long lines to enter the courtroom.

Some wore “Free Luigi” scarves and “Free Luigi” sweaters, and they chanted slogans supporting him and criticizing the American health care industry.

Chelsea Manning, the former United States Army soldier and whistleblower convicted of violating the Espionage Act after leaking documents to WikiLeaks, was spotted among the attendees.

Mangione himself wore a green sweater in that court hearing – a fashion choice that prosecutors said the defense made intentionally.

The defense “has on the one hand cried foul when entities outside the People’s control have made public statements or gestures, while on the other has itself fanned the flames of the public attention,” prosecutors wrote in a recent filing.

Further, prosecutors revealed that Mangione’s attorneys provided him a new pair of argyle socks that contained hidden heart-shaped notes of support.

Mangione’s attorneys later said they “inadvertently did not see” the notes in the socks.

Ulimately, Mangione did not wear those socks during the hearing.