Brother of 'Unabomber' Ted Kaczynski: It's a 'terrible mistake' if he influenced Luigi Mangione

The brother of Ted Kaczynski, the domestic terrorist known as the "Unabomber," said Tuesday that he hopes the man accused in the murder of UnitedHealthcare CEO Brian Thompson didn't view his brother as a "key model" and is distressed that his brother's actions decades ago may motivate violence today.

For two decades, Ted Kaczynski waged a deadly bombing spree that killed three people and injured 23 others until his capture in the Montana wilderness in 1996. Kaczynski had taunted officials with a rambling manifesto and was apprehended following one of the longest FBI manhunts in history.

The suspect in Thompson's killing, Luigi Mangione, an Ivy League tech graduate, had reviewed Kaczynski's "Industrial Society and Its Future," also known as "The Unabomber Manifesto," in January, writing on the book review site Goodreads: "It's easy to quickly and thoughtless write this off as the manifesto of a lunatic, in order to avoid facing some of the uncomfortable problems it identifies. But it's simply impossible to ignore how prescient many of his predictions about modern society turned out."

But David Kaczynski said that his brother, who died by suicide in federal custody in 2023, should not be someone to aspire to.

"His actions are like a virus," David Kaczynski said in a phone interview. "They could be like a virus unless they understand he was a very angry and disturbed man. It doesn't mean his ideas are ideas of a lunatic, but his behavior, I believe, is the behavior of a lunatic."

"To the extent that he may have attributed at all to sort of normalizing or recasting the violent acts as beneficial to humanity is a terrible mistake," David Kaczynski added.

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Ted Kaczynski, a Harvard-educated mathematician, railed against technology in his writings and planted homemade pipe bombs — targeting universities, an American Airlines flight and others — from 1978 to 1995, federal prosecutors said. He wrote a 35,000-word manifesto against the "industrial-technological system" that he hoped would create a revolution in modern society.

Mangione, 26, graduated from the University of Pennsylvania in 2020 with an undergraduate degree in computer science and a minor in mathematics, while simultaneously earning a graduate degree in computer and information science, the school said.

He was arrested Monday at a McDonald's in Altoona, Pennsylvania, following a dayslong manhunt after Thompson's death last Wednesday. The 50-year-old CEO was gunned down in front of a New York City hotel in what the NYPD say was a "premeditated, preplanned targeted attack."

At a hearing Tuesday afternoon in Pennsylvania, Mangione chose to fight extradition to New York, where he would face second-degree murder and other charges. Bail was denied.

Before he entered the courthouse, Mangione shouted toward reporters, "It's completely out of touch and an insult to the intelligence of the American people and their lived experience!"

NYPD Commissioner Jessica Tisch told reporters Monday that investigators found a handwritten document that "speaks to both his motivation and mindset." Further details were not made public, but NYPD Chief of Detectives Joseph Kenny said Mangione appeared to hold "ill will toward corporate America."

In an NYPD preliminary analysis of the shooting, investigators said they are looking at whether the attack was the culmination of the suspect's apparent troubles and list of grievances, including the possibility that the murder was a "symbolic takedown" in a fight against corporate "power games."

Investigators also indicated he may have admired Kaczynski’s attacks and allegedly echoed his own concerns about technological advancement.

Mangione's Goodreads account said he had read 65 titles on topics ranging from Elon Musk to dieting. He rated Kaczynski's book four out of five stars. He also quoted "a take" he found online that he said was "interesting."

The online comment about Kaczynski read, in part: "When all other forms of communication fail, violence is necessary to survive. You may not like his methods, but to see things from his perspective, it’s not terrorism, it's war and revolution."

David Kaczynski was instrumental in helping to capture his brother. After The Washington Post printed "The Unabomber Manifesto" in 1995, David Kaczynski realized his sibling could be one of the FBI's most wanted fugitives and worked with the agency in his capture.

David Kaczynski said he understands that people, to this day, still may look at his brother's writings and find connection with his belief that rapid technological advancement is eroding human freedom. But violence, he added, cannot accompany change.

"I think we always have to remember that human motivation is extremely complicated," David Kaczynski said. "Many factors go into a person's motivation that they drastically act like this, and I hope my brother wasn't in a way a key model for him."

David Kaczynski declined to comment about his brother's death in prison in June 2023. Ted Kaczynski was serving a life sentence without the possibility of parole and had been diagnosed with rectal cancer when he died by suicide at age 81 alone in his cell at the Federal Medical Center in Butner, North Carolina. His autopsy, obtained by NBC News in April, noted he had been "depressed and sent for psychiatric evaluation" a month prior to killing himself.

"Just like acts of love can send out waves of benefit to other people, to humanity at-large in ways we can see and ways we can't see," David Kaczynski said, "acts of violence do the same thing, albeit in a very negative manner. It really gives me a great deal of personal pain to think my brother's actions have in any way contributed to influencing a man like this to kill an innocent human being."