Luigi Mangione exuded a positive demeanor as he returned to court, just days ahead of the anniversary marking his alleged murder of healthcare executive Brian Thompson.

The 27-year-old defendant donned a grey suit and appeared before a judge on Monday. His legal team aimed to prevent potentially incriminating evidence from being presented in his forthcoming trial.

The defense team, representing the Ivy League alumnus, argues that the jury should not be exposed to Mangione’s journal entries, which claim the murder of the former UnitedHealthcare CEO was ‘justified.’

In addition, the defense is challenging the inclusion of items seized when Mangione was apprehended at a McDonald’s in Altoona, Pennsylvania, asserting the lack of a warrant at the time.

The seized items in question include a 3D-printed firearm, a silencer, and various electronic devices.

The young alleged assassin’s arrest a year ago sparked international headlines and made Mangione an anarchist hero, and outside court on Monday legions of his fans gathered to show their support. 

His pre-trial hearing, beginning Monday, could last all week, meaning Mangione may be in court on December 4 – the first anniversary of the day Thompson, 50, was shot dead on the streets of Manhattan. 

Mangione is facing charges in New York of murder in the second degree and criminal possession of a weapon, and he has pleaded not guilty. 

Luigi Mangione appeared upbeat as he arrived back in court on Monday, days before the anniversary of his alleged assassination of healthcare CEO Brian Thompson

The young alleged assassin’s arrest a year ago sparked international headlines and made Mangione an anarchist hero, and outside court on Monday legions of his fans gathered to show their support

In pre-hearing filings, Mangione’s attorneys indicated that they were gearing up to fight key evidence that prosecutors say ties him to Thompson’s murder. 

The evidence focuses on items found on Mangione when he was arrested, including a 9mm handgun that prosecutors say matches the one used in the killing, and a notebook in which they say he described his intent to ‘wack’ a health insurance executive. 

He has denied the charges against him, which had included state terrorism charges that were dropped in September. 

Mangione’s lawyers are now zeroing in on what they say was unconstitutional conduct that tainted his arrest and threatens his right to a fair trial.

They have claimed that officers in Altoona, Pennsylvania, improperly seized evidence from his backpack and questioned him before reading him his rights when they arrested him at a McDonald’s following a five-day long manhunt.

Mangione’s defense team has said that the gun and other items should be excluded because police lacked a warrant to search the backpack in which they were found.

They also want to suppress some of his statements to police, such as Mangione allegedly giving a false name, because officers started asking questions before telling him he had a right to remain silent.

Mangione seen speaking with his attorney as two NYPD officers guard him inside Manhattan Supreme Court on Monday 

Among the evidence that Mangione’s attorneys are attempting to throw out includes his arrest video (pictured) from inside a McDonald’s in Altoona, Pennsylvania 

Prosecutors seized a handwritten diary from Mangione’s backpack during his arrest in Altoona, Pennsylvania that his attorneys are now trying to hide from jurors 

Mangione’s defense is seeking to bar admission of items found in his backpack when he was arrested at a McDonald’s in Altoona, Pennsylvania, because cops didn’t have a warrant – including a 3D printed gun and silencer (pictured) allegedly used in Thompson’s shooting 

UnitedHealthcare CEO Brian Thompson, 50, was shot down as he walked to a Manhattan hotel for his company´s annual investor conference on December 4, 2024

The defense team has argued that body camera footage showing an officer rifling through Mangione’s bag, saying she was checking to ensure there ‘wasn’t a bomb’ inside the backpack, was an excuse ‘designed to cover up an illegal warrantless search of the backpack.’

Eliminating the gun and notebook would be critical wins for Mangione’s defense and a major setback for prosecutors, depriving them of a possible murder weapon and evidence they say points to motive.

The Manhattan District Attorney’s Office has quoted extensively from Mangione´s handwritten diary in court filings including his praise for Unabomber Ted Kaczynski.

In the journal, prosecutors say, Mangione mused about rebelling against ‘the deadly, greed fueled health insurance cartel’ and said killing an industry executive ‘conveys a greedy bastard that had it coming.’

Mangione’s lawyers have further argued that some of the District Attorney’s proposed witnesses should not be tasked with identifying him to the jury, as they were not eyewitnesses to the crime – and had only viewed surveillance footage.

New York State prosecutors have not responded to the defense’s written arguments in the case, but State Supreme Court Justice Gregory Carro is now slated to hear from more than 20 witnesses before he makes a ruling on the admissibility of evidence, according to the New York Daily News.

That may take up much of the week, which Mangione’s attorneys have prepared for by requesting from the Bureau of Prisons five pairs of socks, two suits, three sweaters and three pairs of pants.

Surveillance footage showed a masked man shoot the CEO at point-blank range

Mangione’s lawyers have argued that some of the District Attorney’s proposed witnesses should not be tasked with identifying him to the jury, as they were not eyewitnesses to the crime – and had only viewed surveillance footage

The Ivy League graduate is facing charges in New York of murder in the second degree, criminal possession of a weapon for the shocking point-blank murder nearly one year ago

Thompson was shot down as he walked to a Manhattan hotel for his company´s annual investor conference on December 4, 2024.

Surveillance footage from the attack showed a masked gunman shooting him from behind. Police say ‘delay,’ ‘deny’ and ‘depose’ were written on the ammunition, mimicking a phrase used to describe how insurers avoid paying claims.

The crime and Mangione’s ensuing arrest led him to become somewhat of a celebrity, with his fans saying that he had taken a ‘bite out of corruption’ when he allegedly shot Thompson, 50, dead.

Mangione has since become a ‘symbol’ for the fight for healthcare reform, his supporters said, as they send him as many as 200 letters a day while he serves time inside the notorious Metropolitan Detention Center Brooklyn.

Those supporters are now expected to show up en masse this week to the preliminary court hearings to cheer on their hero, who is facing life in prison on the New York state charges and the death penalty on the federal charges.

His lawyers want to bar evidence from both cases, but this week’s hearings pertain only to the state case.

Meanwhile, federal prosecutors have said in their own court filings that police were justified in searching Mangione’s backpack to ensure there were no dangerous items.

They noted that the contents of the backpack ‘would have inevitably been discovered’ during an inventory search anyway.

Federal prosecutors also argued in their filing last week that the only pre-Miranda statement they plan to use against Mangione is when he allegedly gave officers a fake name.

At that point, the government argued, ‘no Miranda warnings were required.’

Much of the filing, though, rebuked Mangione’s lawyers after they claimed that statements made by President Donald Trump and Attorney General Pam Bondi have irreparably prejudiced the case.

The defense accused Trump of repeatedly intervening in the case, pointing to a series of public comments and official actions they say connected Mangione to Antifa.

The lawyers cited Trump’s September 25 proclamation, ‘Countering Domestic Terrorism and Organized Political Violence,’ which referenced ‘the assassination of a senior healthcare executive’ as part of a trend of politically motivated violence influenced by Antifa.

The proclamation did not name Mangione, but his defense team argues it clearly referred to their client.

Mangione’s defense team previously asked a judge to dismiss the federal indictment arguing that comments from Trump have irreparably prejudiced the case

Mangione’s attorneys also renewed allegations of political interference by Attorney General Pam Bondi (pictured), who in April directed federal prosecutors to seek the death penalty 

Defense attorneys also cited a September 18 Fox News interview in which Trump said Mangione ‘shot someone in the back as clear as you’re looking at me’ and called the act ‘a sickness.’

The next day, White House-affiliated X account Rapid Response 47 shared the clip with its 1.2 million followers. 

According to the defense, the post was later reposted by Justice Department deputy public affairs director Chad Gilmartin, who wrote that Trump ‘is absolutely right.’

‘Mr. Mangione is one young man, alleged to have acted alone, fighting for his life in three separate cases, against the full force and might of the entirety of the United States Government that is actively and persistently using him as a pawn to further its political agenda,’ Mangione’s attorneys wrote in their plea to get the death penalty dropped.

‘This is the very definition of prejudicial where the consequence is death.’

Federal prosecutors, however, told the court they had the posts removed after learning of them and argued the officials involved were not part of the prosecution team.

‘They operate entirely outside the scope of the prosecution team, possess no operational role in the investigative or prosecutorial functions of the Mangione matter, and are not ‘associated’ with this litigation,’ prosecutors said in a letter.

Mangione’s attorneys also renewed allegations of political interference by Bondi, who in April directed federal prosecutors to seek the death penalty, calling it part of ‘President Trump’s agenda to stop violent crime and Make America Safe Again.’

In a Fox News interview that month, Bondi said, ‘If there ever was a death [penalty] case, this is one.’

The defense argues Bondi’s comments, along with Trump’s public statements, have ‘poisoned the jury pool’ and violated Mangione’s due process rights.

But in their filing, prosecutors argued that ‘public rhetoric by the Attorney General or the President is not a proxy for proof of prejudicial effect,’ citing precedent that ‘in the absence of clear evidence to the contrary, courts will presume that prosecutors have discharged their duties properly.’