Luigi Mangione wrote in a manifesto found on him that health care executives were 'parasites [who] had it coming.'
The 26-year-old was arrested Monday at Pennsylvania McDonald’s after a worker alerted authorities to a customer who resembled the suspected gunman.
He has since been charged with the murder of UnitedHeathCare CEO Brian Thompson in midtown Manhattan.
Mangione's family issued a statement after his arrest, saying they were shocked and devastated.
'Unfortunately, we cannot comment on news reports regarding Luigi Mangione," the Mangione family said. 'We only know what we have read in the media.
'Our family is shocked and devastated by Luigi's arrest. We offer our prayers to the family of Brian Thompson and we ask people to pray for all involved.'
Mangione comes from a prominent Maryland family. His grandfather Nick Mangione, who died in 2008, was a successful real estate developer.
One of his best-known projects was Turf Valley Resort, a sprawling luxury retreat and conference center outside Baltimore that he purchased in 1978.
Luigi Mangione singled out UnitedHealthcare in manifesto as he appears in court after CEO assassination
The suspected gunman reportedly referenced UnitedHealthcare in the handwritten document found on him.
Luigi Mangione mentioned the $515.93 billion company in his manifesto noting the size of the company and how much money it makes, a senior law enforcement offical who saw the document told the New York Times.
In the 262-word handwritten manifesto, Mangione said as UnitedHealthcare’s market capitalization has grown, American life expectancy has not.
The document condemned companies that 'continue to abuse our country for immense profit because the American public has allowed them to get away with it.
He reportedly wrote that acted alone and that he was self-funded.
'To save you a lengthy investigation, I state plainly that I wasn’t working with anyone,' Mangione said.
'These parasites had it coming. I do apologize for any strife and trauma, but it had to be done.'
Fundraiser for alleged killer emerges after arrest
A GiveSendGo page has raised over $6,000 of its $200,000 goal for alleged killer Luigi Mangione.
'This is a preemptive legal fundraiser for the suspect allegedly involved in the shooting of the United Healthcare CEO,' the page reads.
'We are not here to celebrate violence, but we do believe in the constitutional right of fair legal representation.'
'Please share in your networks!'
Watch: Luigi Mangione's valedictorian speech at $40k-a-year prep school
Luigi Mangione told his classmates they need 'incredible courage to explore the unknown and try new things.'
Mangione had served as the valedictorian of Gilman School's Class of 2016, which he praised in his speech for its 'inventive [and] pioneering mentality.'
Pennsylvania Gov. Josh Shapiro said Luigi Mangione 'is no hero'
Gov. Josh Shapiro said suspected UnitedHealthcare CEO shooter Luigi Mangione is 'no hero' following his court appearence.
'In America, we do not kill people in cold blood to resolve policy differences or express a viewpoint,' Shapiro said.
'He is no hero. The real hero in this story is the person who called 911 at McDonald's this morning.'
Luigi Mangione believed to be in Pennsylvania for 'several days'
Suspected UnitedHealthcare CEO shooter has been in the Keystone State for 'several days' following the deadly attack, according to police.
Pennsylvania State Police Lt. Col. George Bivens said police are working to piece together where the suspect went following Brian Thompson's assassination.
'We know that he has been in Pennsylvania for several days, so part of that investigation will also focus on trying to retrace his steps,' Bivens said.
Luigi Mangione's startled reaction as McDonald's workers IDed suspected assassin
NYC officials charge Luigi Mangione with murder of UnitedHealthcare CEO Brian Thompson
Luigi Mangione was charged with murder by NYC officials for the shock execution of UnitedHealthcare CEO Brian Thompson.
He was detained on Monday by police in Pennsylvania.
Mangione now faces three gun charges and forgery in New York.
He remains jailed in Pennsylvania on charges of possession of an unlicensed firearm, forgery and providing false identification to police.
Mangione was arrested in an Altoona McDonald's on Monday after cops 'immediately recognized' him as the suspect in the murder of UnitedHealthcare CEO Brian Thompson.