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.'