Revealed: Chilling details of hand-written 'manifesto' found in healthcare boss 'assassin' Luigi Mangione's backpack

Chilling new details of Luigi Mangione's manifesto that was found in his backpack when he was arrested in a Pennsylvania McDonald's have emerged, five days after allegedly murdering UnitedHealthcare CEO Brian Thompson in New York City.

Mangione, a 26-year-old Ivy League-educated 'anti-capitalist' was taken into custody after a McDonald's employee in Altoona, around 100 miles east of Pittsburgh, believed they recognized him as the gunman who murdered UnitedHealthcare's CEO Brian Thompson on December 4. 

Mangione is alleged to have gone on the run after the killing, with cops finding him five days later in Pennsylvania. 

At a press conference, the NYPD's chief of detectives Joseph Kenny said Mangione had a three-page, handwritten document that shows 'ill will toward corporate America.'

A law enforcement official who wasn't authorized to discuss the investigation publicly and spoke with The Associated Press on condition of anonymity said the document included a line in which Mangione claimed to have acted alone.

'To the Feds, I'll keep this short, because I do respect what you do for our country. To save you a lengthy investigation, I state plainly that I wasn't working with anyone,' the document said, according to the official.

It also had a line that said, 'I do apologize for any strife or traumas but it had to be done. Frankly, these parasites simply had it coming.'

At the scene of the killing, cops found bullets and bullet casings with the words 'delay', 'deny' and 'depose' scrawled on them. The words mimic a phrase used to criticize the insurance industry.  

Pennsylvania prosecutor Peter Weeks said in court that Mangione was found with a passport and $10,000 in cash - $2,000 of it in foreign currency. Mangione disputed the amount when he was arraigned. 

Thompson, 50, was killed last Wednesday as he walked alone to a midtown Manhattan hotel for an investor conference. Police quickly came to see the shooting as a targeted attack by a gunman who appeared to wait for Thompson, came up behind him and fired a 9 mm pistol.

Investigators have said 'delay,' 'deny' and 'depose' were written on ammunition found near Thompson's body. The words mimic a phrase used to criticize the insurance industry.

Mangione was arrested in Altoona, Pennsylvania, after the McDonald's customer recognized him and notified an employee, authorities said. Police in Altoona, about 233 miles (375 kilometers) west of New York City, were soon summoned.

They arrived to find Mangione sitting at a table in the back of the restaurant, wearing a blue medical mask and looking at a laptop, according to a Pennsylvania police criminal complaint.

He initially gave them a fake ID, but when an officer asked Mangione whether he'd been to New York recently, he 'became quiet and started to shake,' the complaint says.

When he pulled his mask down at officers' request, 'we knew that was our guy,' rookie Officer Tyler Frye said at a news conference in Hollidaysburg.

New York Police Commissioner Jessica Tisch said at a Manhattan news conference that Mangione was carrying a gun like the one used to kill Thompson and the same fake ID the shooter had used to check into a New York hostel, along with a passport and other fraudulent IDs. 

From surveillance video, New York investigators gathered that the shooter fled by bike into Central Park, emerged, then took a taxi to a northern Manhattan bus terminal.

Once in Pennsylvania, he went from Philadelphia to Pittsburgh, 'trying to stay low-profile' by avoiding cameras, Pennsylvania State Police Lt. Col. George Bivens said.

A grandson of a wealthy, self-made real estate developer and philanthropist, Mangione is a cousin of a current Maryland state legislator. Mangione was valedictorian at his elite Baltimore prep school, where his 2016 graduation speech lauded his classmates' 'incredible courage to explore the unknown and try new things.' 

Mangione graduated top of his class from the elite Gilman School in Baltimore, and even delivered the commencement speech at his 2016 graduation, according to video of the ceremony.

'He seemed like a smart kid, he was always doing the right thing, it seemed like,' a former classmate, who was shocked by the arrest, told Fox News Digital, adding: '[He] wasn't crazy.'

He went on to earn undergraduate and graduate degrees in computer science in 2020 from the University of Pennsylvania, a spokesperson said.

'Our family is shocked and devastated by Luigi's arrest,' Mangione's family said in a statement posted on social media late on Monday by his cousin, Maryland lawmaker Nino Mangione. 'We offer our prayers to the family of Brian Thompson and we ask people to pray for all involved.'

Luigi Nicholas Mangione worked for a time for the car-buying website TrueCar and left in 2023, CEO Jantoon Reigersman said by email.

From January to June 2022, Mangione lived at Surfbreak, a 'co-living' space at the edge of Honolulu tourist mecca Waikiki.

Like other residents of the shared penthouse catering to remote workers, Mangione underwent a background check, said Josiah Ryan, a spokesperson for owner and founder R.J. Martin.

'Luigi was just widely considered to be a great guy. There were no complaints,' Ryan said. 'There was no sign that might point to these alleged crimes they're saying he committed.'

At Surfbreak, Martin learned Mangione had severe back pain from childhood that interfered with many aspects of his life, from surfing to romance, Ryan said.

'He went surfing with R.J. once but it didn't work out because of his back,' Ryan said, but noted that Mangione and Martin often went together to a rock-climbing gym.

Mangione left Surfbreak to get surgery on the mainland, Ryan said, then later returned to Honolulu and rented an apartment.

Martin stopped hearing from Mangione six months to a year ago.

Although the gunman obscured his face during the shooting, he left a trail of evidence in New York, including a backpack he ditched in Central Park, a cellphone found in a pedestrian plaza, a water bottle and a protein bar wrapper.

In the days after the shooting, the NYPD collected hundreds of hours of surveillance video and released multiple clips and still images in hopes of enlisting the public's eyes to help find a suspect.

'This combination of old-school detective work and new-age technology is what led to this result today,' Tisch said at the New York news conference.