A year after a mysterious gunman attacked UnitedHealthcare CEO Brian Thompson near a Manhattan hotel, the suspect in the case is attempting to exclude critical evidence that authorities claim links him to the crime. However, legal experts suggest his odds of success are minimal.

Luigi Mangione, the accused gunman, is petitioning a New York judge to dismiss evidence obtained from his backpack without a warrant. This evidence includes the alleged murder weapon, journals purportedly revealing his motives and strategies, and statements made by him before and after his capture.

“The defense’s arguments aren’t entirely implausible, and they warrant a hearing to be considered,” stated Christopher Slobogin, a Vanderbilt University Law School expert and head of its criminal justice program. “The case’s complexity necessitates a hearing longer than a single day to ascertain the pertinent facts.”

Nevertheless, Slobogin told Fox News Digital that Mangione’s legal maneuvers, at 27 years old, face considerable odds and remain “long shots.”

“These are not totally implausible arguments being made by the defense and to allow those arguments to be made there has to be a hearing,” said Christopher Slobogin, a Vanderbilt University Law School scholar and director of its criminal justice program. “And the facts are complicated enough that the hearing apparently has to be more than one day in order to establish the relevant facts.”

Still, he told Fox News Digital that the 27-year-old Mangione’s arguments are all “long shots.”

Luigi Mangione, the Ivy League graduate charged with executing the head of America’s largest healthcare company on a Midtown sidewalk, is back in Manhattan court for an evidence hearing that could make or break his state case. (Steven Hirsch for New York Post via Pool)

“The Supreme Court of the United States has made it very clear that if a person’s been lawfully arrested, the police can do a warrantless search incident to that arrest of any objects on the individual’s person except for their cellphone,” he said.

On Dec. 9, 2024, staff and customers at a McDonald’s in Altoona, Pennsylvania, called 911 to report a suspicious man eating alone in the corner who bore a resemblance to the “person of interest” New York police were seeking in connection with Thompson’s assassination.

Read Mangione’s April 30 motion:

Officers arrived and one of them said he recognized Mangione from the wanted poster as soon as he took his mask down. He allegedly provided a fake name and ID, which is what led to the initial charges in his arrest.

This 2017 file photo of Brian Thompson was released via Businesswire when he was named Chief Executive Officer of UnitedHealthcare Unit in 2017. (Businesswire)

Mangione has been in court for most of the week for oral arguments on an April motion in which his lawyers argued that police improperly obtained statements in violation of his Fifth Amendment right to remain silent and that the warrantless search violated his Fourth Amendment protections against unreasonable searches.

“The arguments are probably long shots, but they’re not without merit,” said Josh Ritter, a Los Angeles criminal defense attorney and Fox News contributor. “The problem is that factually, it’s a fact-intensive inquiry being made by the judge, and the facts are just not in their favor.”

Judge Gregory Carro has not yet made a decision on whether the evidence will be allowed, but prosecutors have countered that police conducted themselves properly and did not violate Mangione’s constitutional rights, as the defense argued.

Sketch of Luigi Mangione in Manhattan Criminal Court for an evidence hearing, Tuesday, Dec. 2, 2025, in New York.  (Jane Rosenberg)

Mangione allegedly handed officers a phony New Jersey ID with the name “Mark Rosario” on it — the same ID police allege he used to check into a hostel in Manhattan before the murder. He also gave the false name to police when they asked who he was, according to testimony from the arresting officers and bodycam video played in court.

He was later Mirandized, frisked and arrested — and then police searched his bag. They did not have a warrant for the search, but authorities say the search was incidental to his arrest and therefore permissible.

“They have no leg to stand on with a fake name and fake ID,” said Donna Rotunno, a Chicago criminal defense attorney and Fox News contributor. “The police have an absolute right to ask you to identify yourself.”

UnitedHealthcare CEO slaying suspect Luigi Mangione pictured at a McDonald’s in Altoona, Pennsylvania, on Monday, Dec. 9, 2024. (Pennsylvania State Police)

Later, while awaiting extradition to New York in a Pennsylvania jail cell, he allegedly told a guard he had a 3D-printed gun and foreign cash in his bag when he was arrested.

The guard, Matthew Henry, testified that he hadn’t asked Mangione about it, did not respond, and wasn’t interested in talking to Mangione at the time.

“I also think the statement regarding the gun once he’s in lock-up and already under arrest is going nowhere,” Rotunno said. “It would be very bizarre for lock-up officers to be questioning anyone. Also, this is not a dumb guy… I don’t think he would be responding with information after he asked for a lawyer. It sounds like it’s much more plausible that he was proud of what he did and wanted to put it out there.”

Thompson, a 50-year-old father of two from Minnesota, was in New York City for an investor conference when a masked man shot him in the back outside a midtown Hilton hotel. The NYPD recovered shell casings at the scene with words written on them that are believed to be a reference to a book about how health insurance companies avoid paying claims.

A screenshot from surveillance footage released by the NYPD shows an alleged person of interest wanted in connection with the shooting death of UnitedHealthcare CEO Brian Thompson in Midtown Manhattan on Wednesday, Dec. 4, 2024.   (NYPD Crime Stoppers )

Mangione’s defense has already succeeded in another aspect of the April motion — in which his lawyers asked the judge to toss terrorism charges that would have made the maximum penalty life without parole if convicted.

His top charge in New York is now second-degree murder, which carries a maximum sentence of life in prison — with parole on the table.