Luigi Mangione's secret diary entries have exposed chilling details about his alleged plot to assassinate UnitedHealthcare CEO Brian Thompson. The 27-year-old suspect's personal writings, contained in a red notebook, were discovered upon his arrest following a five-day manhunt.

According to Daily Mail, prosecutors filed court documents Wednesday revealing the contents of Mangione's diary, which meticulously documented his planning and motivations for the December 2024 shooting. The entries show he had been contemplating the murder for months, with one entry dated August 15, 2024, stating he felt "confident" about his plan and believed it to be "right/justified."

In another diary passage, Mangione wrote about his decision to target the healthcare industry, describing it as "parasitic" and referring to employees as "mafioso." The notebook also contained his musings on Unabomber Ted Kaczynski, with Mangione criticizing Kaczynski's methods while seemingly attempting to learn from what he perceived as mistakes in the notorious terrorist's approach.

Months of Premeditation Revealed

Evidence presented in court suggests Mangione had been planning the assassination at least four months before carrying it out. In his August entry, he wrote: "I finally feel confident about what I will do. The details are coming together. And I don't feel any doubt about whether it's right/justified."

The diary also revealed that Mangione had initially considered a different target, referred to only as "KMD," before deciding to focus on UnitedHealthcare. "KMD would have been an unjustified catastrophe that would be perceived mostly as sick, but more importantly unhelpful," he wrote, adding that it "would do nothing to spread awareness/improve people's lives. The target is insurance. It checks every box."

Prosecutors have described the case against Mangione as "open and shut," citing the diary entries as proof of both his identity as the shooter and the premeditated nature of the crime.

Manhattan Assistant District Attorney Joel Seidemann wrote in the filing that "one would be hard pressed to find a case with such overwhelming evidence of guilt as to the identity of the murderer and premeditated nature of the assassination."

Unabomber Comparisons and Strategy

Mangione's diary contained extensive references to Ted Kaczynski, showing how he analyzed the Unabomber's tactics while formulating his own approach. In an October 2024 entry, he acknowledged that while Kaczynski "makes some good points on the future of humanity," he believed Kaczynski's methods were counterproductive.

"Normies characterize him as an insane serial killer, focus on the act/atrocities themselves and dismiss his ideas," Mangione wrote, explaining why he believed Kaczynski's bombing campaign had been ineffective in conveying his message. He added that because of Kaczynski's "indiscriminate atrocities," he "becomes a monster, which makes his ideas those of a monster, no matter how true."

Instead of bombing a headquarters, which Mangione associated with terrorism, he outlined his plan to "wack" the CEO at what he called a "parasitic bean-counter convention." He wrote that such an action "doesn't risk innocents" and that "the point is made in the news headline 'Insurance CEO killed at annual investors conference.'"

Murder and Aftermath Details

Court documents reveal new information about the hours before the shooting, suggesting Mangione stalked Thompson the night before the murder. Prosecutors allege surveillance footage captured him walking near the Hilton Hotel on December 3, around 7:47 p.m., as Thompson walked past him in the opposite direction.

The next morning, December 4, Thompson was shot and killed outside the Hilton Hotel in Midtown Manhattan while heading to UnitedHealthcare's annual conference. Security footage showed a masked assailant approaching from behind and shooting the 50-year-old father of two at point-blank range before escaping on a bicycle into Central Park.

Evidence recovered at the scene included bullet and shell casings marked with the words "deny," "delay," and "depose" – a phrase commonly associated with health insurance claims processing. After a five-day manhunt, Mangione was arrested at a McDonald's in Altoona, Pennsylvania, and subsequently charged with the murder.

Why This Story Matters

This story underscores how targeted violence can be used to send a political message, even in settings where professionals and executives gather to do business. It exposes the vulnerability of public figures and raises important questions about how we define and prosecute terrorism. Finally, it reminds communities to take ideological radicalization seriously before it leads to tragedy.

Conclusion

Luigi Mangione is charged in connection with the December 4 murder of UnitedHealthcare CEO Brian Thompson. Prosecutors say his red diary details months of planning and anti-healthcare motivations. Surveillance footage, disturbing handwritten notes, and damning shell casing inscriptions all support the state’s case for ideological terrorism. Mangione has pleaded not guilty and awaits his June court date, facing potentially the death penalty if convicted.