CEO Murder Defendant Luigi Mangione States Lack of Shame In Manifesto: ‘These Parasites Had It Coming’

Police have described obtaining what a law enforcement source described to PEOPLE as the “manifesto” of Luigi Mangione, the man accused of murdering UnitedHealthcare CEO Brian Thompson. In the three-page document, which was found on Mangione’s person, he allegedly claimed the murder “had to be done.”

Mangione is now charged with murder as he’s jailed in Pennsylvania, where he was arrested following a six-day manhunt that began in New York City.

After Mangione was arrested at a McDonald’s in Altoona, Pa., authorities claim they found a “ghost gun,” a silencer and fake IDs, as well as the manifesto.

A law enforcement source tells PEOPLE that in the manifesto, Mangione allegedly stated: “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.”

“I do apologize for any strife or traumas, but it had to be done,” Mangione allegedly continued. “Frankly, these parasites had it coming.”

Mangione was taken into custody after a McDonald’s customer told an employee that the 26-year-old, who was wearing a mask and looking at a computer in the fast food restaurant, looked suspicious, according to a criminal complaint. The employee then called police.

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Thompson was killed outside the New York Hilton Midtown hotel in Manhattan as he was walking to an annual investor event.

Widely circulated video footage of the shooting on Dec. 4 appears to show a masked and hooded man fire multiple shots at Thompson.

Shell casings found at the scene reportedly had the words “deny,” “defend” and “depose” on them — a possible reference to “deny, delay, defend,” a phrase used about the insurance industry to describe a strategy of rejecting claims.

Mangione also faces charges in Pennsylvania after allegedly being found with a gun and showing a fake ID to a police officer. He has not yet entered a plea.