After a hike through one of Japan’s lush mountain ranges earlier this year, Luigi Mangione, a computer engineer in his mid-20s who had set off on a long solo trip to Asia, paused to record a voice message to a friend.

Making his way that day along a river gorge in the Nara region, Mangione had fled his day-to-day life in Hawaii to soak in hot springs, meditate, catch up on books and do some writing of his own.

“I want some time to Zen out,” Mangione said in the recorded message on April 27.

It would be one of his last communications before he abruptly cut ties with a wide range of friends and family, who eventually set out on a desperate hunt to track him down. Seven months later, Mangione emerged from his isolation as the suspect in the brazen assassination of Brian Thompson, the chief executive of Minnesota-based UnitedHealthcare, on a sidewalk in Manhattan.

Police investigators have been scrambling to trace Mangione’s movements not only in the days before the Dec. 4 shooting, but also in the months that preceded it.

Friends and family members have been left bewildered by the jarring transformation of a young man who had seemed destined for a life of achievement. He was the valedictorian at his elite prep school in Maryland and a computer science graduate of the University of Pennsylvania’s acclaimed engineering program.

But his writings and messages also traced a darker journey in “unbearable pain.”

He expressed alarm over the world’s increasing reliance on smartphones and social media. During his trip to Asia, he lashed out at the “modern Japanese urban environment,” claiming that a lack of “natural human interaction” were responsible for falling birthrates and a dearth of human connection.

More and more, he expressed frustration that society seemed incapable of addressing these problems, and he expressed interest in those who said that violence might be a necessary next step.

In his possession at the time of his arrest in Altoona, Pa., police said, were writings that condemned a multibillion-dollar health care industry that he said had put profits ahead of extending lives: “Frankly, these parasites simply had it coming.”

Mangione is now charged with second-degree murder in the death of Thompson. His defense lawyer, Thomas Dickey, said his client was presumed innocent and urged the public to keep an open mind.

‘Life-halting issue’

Mangione’s medical struggles seemed to escalate during his studies at the University of Pennsylvania. Underneath Mangione’s friendly, accomplished exterior, he was struggling to adapt to college.

He wrote on social media that his fraternity’s “hell week,” despite being “very tame,” had disturbed his sleep cycle and drastically worsened symptoms of “brain fog” that he had been experiencing since high school. Once a straight-A student, Mangione wrote in a series of since-removed posts on Reddit that he suddenly saw his grades slipping.

“It’s absolutely brutal to have such a life-halting issue, especially since the issue itself wears down the critical/logical thinking mind you’d usually use to tackle it,” he wrote. “The people around you probably won’t understand your symptoms — they certainly don’t for me.”

As the pandemic arrived during his senior year in 2020, Mangione completed both a bachelor’s degree and a master’s degree simultaneously. He soon secured a job at a California-based tech company.

Able to work remotely, Mangione moved in early 2022 to Honolulu, settling into a co-living space in a high-rise near Waikiki. But soon after, his medical troubles worsened following a group surfing lesson, and he complained that he had strained his back.

“His spine was kind of misaligned,” said R.J. Martin, who had founded the co-living space and grew to be friends with Mangione. “He said his lower vertebrae were almost like a half-inch off, and I think it pinched a nerve. Sometimes he’d be doing well and other times not.”

For months, the suffering continued as he consulted with doctors and tried a variety of noninvasive remedies. He quit his job in early 2023, telling a friend that it was “mind-numbingly boring.” He said he wanted to spend more time doing yoga and reading.

But it is not clear how he paid for health care after that. In May, he turned 26, meaning that he could have been kicked off his parents’ health insurance plan. The family has declined requests for interviews.

Unabomber’s manifesto

Mangione had always been a voracious reader, scribbling extensive notes that would summarize the author’s views and how they might apply to his own life.

“Reflect on how current work can positively impact society,” he wrote while reading “Grit: The Power of Passion and Perseverance,” a book about how to overcome setbacks by intentionally cultivating tenacity.

Among his friends in Hawaii, he helped start a book club that began meeting in 2023. Mangione pushed for readings by Tim Urban, a writer-illustrator whose blog “Wait, But Why,” is popular with Gen Z techies. The group also read “The Ape That Understood The Universe,” a favorite of Mangione’s that explores evolutionary psychology.

One focus of his reading was his ongoing back troubles, including “Crooked: Outwitting the Back Pain Industry and Getting on the Road to Recovery.” In the summer of 2023, he decided it was time to pursue surgery, traveling back to the East Coast for the procedure.

He reported on Reddit that the procedure was a success and began encouraging others to consider surgery. He suggested at one point that people should perhaps tell their doctor that their back troubles were preventing them from working.

“We live in a capitalist society,” he wrote. “I’ve found that the medical industry responds to these key words far more urgently than you describing unbearable pain and how it’s impacting your quality of life.”

There was a growing strain among members of his book group, participants said. Some of them were perturbed by Mangione’s book selections, which they felt were overly geared toward masculine pursuits. Others drifted away after a discussion about whether to read the writings of Ted Kaczynski, the so-called Unabomber.

Martin said he was the one who proposed reading Kaczynski’s manifesto, but Mangione was also clearly a fan, praising it later on his Goodreads page. Mangione quoted what he described as “interesting” remarks from someone who had written about how companies “have zero qualms about burning down the planet for a buck, so why should we have any qualms about burning them down to survive?”

The passage went on, “How long until we recognize that violence against those who lead us to such destruction is justified as self-defense?”

Traveling abroad

After his surgery, Mangione toured the islands of Hawaii, visited family back in Maryland and then, early this year, set off on the trip to Asia.

He wrote that he found Japan’s densely urban environment to be “an evolutionary mismatch for the human animal.” But he loved the mountains, saying that one of his goals in Asia was to “do some Buddha.”

One of the people he spoke to during his travels was Gurwinder Bhogal, a writer who was living in England. Bhogal recalled Mangione leaning to the left on some political issues and to the right on others, and that he was interested in effective altruism.

“Overall, the impression I got of him, besides his curiosity and kindness, was a deep concern for the future of humanity, and a determination to improve himself and the world,” Bhogal said.

On May 25, Mangione’s Reddit account shows one final post, on a subreddit dedicated to Kaczynski.

Not long after that, friends started to lose touch with Mangione. One texted him in June — “Where in the world are you?” — but received no reply. By the end of the summer, family members were reaching out to Mangione’s past friends, hoping for their help in tracking him down.

His relatives have not discussed why they waited until Nov. 18 to file a missing person’s report in California.

Just a few days later, police say, Mangione got on a bus, on his way to New York City.