For years before he was accused of killing the CEO of one of America's largest health-insurance companies, Luigi Mangione suffered from debilitating pain that doctors didn't seem able to fix.

He detailed the pain, and what he felt to be the healthcare system's inadequate response, in dozens of posts on Reddit between 2018 and 2024.

None of them, though, mention UnitedHealthcare or its CEO, Brian Thompson, whom he's now accused of killing. And none of the posts blame UnitedHealthcare — or Thompson — for his health issues. The only insurer mentioned is Blue Cross Blue Shield, in a brief post describing how it covered a medical test.

But his posts paint a portrait of someone whose pain and recovery led him to put "my life on hold in my 20s." And the experience appears to represent a significant — and excruciating — engagement with the American healthcare system. Like most young Americans, if Mangione was covered by his parents' health-insurance plan, he likely would have aged out when he turned 26 in May, under rules set by the Affordable Care Act.

In handwritten notes from 2019 reviewed by Business Insider, Mangione wrote that he had spondylolisthesis — severe slippage of parts of the spine due to joint deterioration.

In 2022, he described "near-constant burning/twitching in both ankles/calves." By 2023, he wrote on Reddit, he'd been experiencing "back and genital pain" on and off for a year, including numbness in his groin. (Details shared by the Reddit account match biographical details about Mangione sourced from public documents.)

He underwent surgery later that year. An X-ray image Mangione posted on social media depicted a spinal fusion, with rods and screws reinforcing the position of his bones. At first, he appeared jubilant — his pain was gone. But by June this year, he was castigating doctors as "basically worthless" on X.

Public records, social-media posts, and interviews indicate that Mangione cut off contact with family and friends earlier this year. Months later, police say Mangione murdered Thompson on a Manhattan sidewalk, wielding a gun assembled from 3D printed parts.

The scion of a prominent Baltimore family, Mangione was educated at elite schools. Friends say they're now hard-pressed to recognize the kind, unassuming, and whip-smart person they know.

A classmate who led a student group at the University of Pennsylvania with Mangione in 2016 and 2017 said she recalled him as humble, helpful, and immensely driven. She asked not to be named given the intense focus on Mangione, but BI has confirmed her identity.

"I would set my sister or friend up with him," she said. "Just knowing his personality, I would completely trust him. Even knowing what I know now, if he 100% did it, I would feel completely safe being alone in a room with him."

A privileged youth

Mangione grew up in Towson, Maryland, about 10 miles outside Baltimore. His grandfather, Nick Mangione Sr., was a self-made multimillionaire, The Baltimore Banner reported. The elder Mangione, who died in 2008, owned and operated a sprawling portfolio of country clubs, nursing homes, and local radio stations. The younger Mangione is one of 37 grandchildren, part of a large family whose ranks also include a Maryland lawmaker.

Mangione's parents and immediate family did not respond to requests for comment.

Thomas J. Maronick Jr., an attorney and longtime host at one of the family's radio stations, told BI that the family was "very influential" in the local community, which was reeling from the news of Mangione's arrest.

"When you think of the Mangione family, you think of an esteemed family that has done a lot for the community," Maronick said on a phone call. "When I first heard the name, I thought it had to be a different family. It was very out of character for anything I've ever known about the family."

Mangione appeared well positioned to carry on the family's name.

He attended the Gilman School, a prestigious Baltimore-area all-boys school where tuition runs over $37,000 a year. There, he cofounded AppRoar Studios, a company that released a phone game; was in the school's robotics club; and graduated as valedictorian of the class of 2016.

Mangione was "very into sports" and "very social," a high-school classmate told BI. The classmate asked not to be named, but BI has verified their identity. "He was easily one of the smartest in our class. I never would have thought he would have been a part of this," the classmate added.

He went on to the University of Pennsylvania, graduating in four years with both a bachelor's and a master's degree in computer science, a university spokesperson said. He cofounded a video-game-design club and was inducted into the computer-engineering department's Eta Kappa Nu society for students at the top of their class, according to blog posts and the society's website.

He appeared active in his fraternity, photos posted on Instagram show.

Still, his health appeared to drag him down. In posts on Reddit, he described experiencing "brain fog." His "cognitive decline" started after he contracted Lyme disease at 13, he wrote, and worsened after his "very tame" but sleepless fraternity initiation. The fraternity did not respond to a request for comment.

He considered dropping out of college, he wrote, and felt that his condition restricted him to "what feels like 10% of a college experience."

"My symptoms were very minor at first and I was able to excel in high school, but the symptoms worsened exponentially last year," he wrote in 2018. "It's absolutely brutal to have such a life-halting issue."

In 2019, Mangione spent three months as a counselor for a Stanford summer program for high schoolers. He left a positive impression on the students, one of them said in posts on Instagram.

After college, he got a job as a data engineer at TrueCar, an online vehicle-purchase platform, and was regularly promoted, according to his LinkedIn profile and a former colleague.

By early 2022, he had moved to a coliving space in Hawaii called Surfbreak, according to photos posted on Instagram. R.J. Martin, the founder of Surfbreak, told Honolulu Civil Beat that Mangione founded a book club at the residence. On Martin's suggestion, one of the books discussed by the club was the Unabomber Ted Kaczynski's manifesto, Martin said.

Kaczynski, a Harvard-trained mathematician, lived in the wilderness and conducted a 17-year mail-bombing campaign against people he blamed for advancing technology at the expense of the natural environment.

Mangione gave the book four out of five stars on his Goodreads account.

"While these actions tend to be characterized as those of a crazy luddite, however, they are more accurately seen as those of an extreme political revolutionary," Mangione wrote in his review of the book.

The book club dissolved shortly thereafter, Martin told Civil Beat, amid discomfort with the manifesto.

Mangione detailed his back-pain journey on social media

In Hawaii, Mangione experienced another health setback. He'd had mild back pain since he was a child, but while surfing in early 2022, he "experienced sciatica for the first time," he wrote on Reddit. "A few weeks later I slipped on a piece of paper and my right glute locked and right leg shut down for a week. Couldn't support any weight on it."

Mangione, writing under the username Mister_Cactus, was a frequent poster in the spondylolisthesis subreddit. He exchanged notes with other people dealing with the condition and advised one poster how to persuade medical professionals to take symptoms seriously in the face of some doctors whose perspectives he decried as "nonsense."

"Tell them you are 'unable to work'/do your job. 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."

Martin told Honolulu Civil Beat that Mangione struggled with back pain throughout his time living at Surfbreak in 2022. In a separate interview, with The New York Times, Martin said that Mangione told him the lower vertebrae of his spine were nearly "a half-inch off" and had impeded his romantic life.

But by the next year, Mangione wrote that surgery had helped resolve his pain, at least for a time.

In one post, dated October 2023, he said back-fusion surgery had been "a success." After a week, he had no use for pain medication, he wrote.

"The surgery wasn't nearly as scary as I made it out to be in my head, and I knew it was the right decision within a week, and that I won't have to bother with injections or future surgery for many years," he wrote.

Mangione went dark earlier this year

In 2023, Mangione stopped working at TrueCar. The company laid off more than 100 employees that year. BI was unable to confirm the circumstances under which he left the company.

He appeared to spend early 2024 traveling around Asia, according to Reddit posts. In April, he emailed the author of a Substack he followed to say he would be in Japan through the beginning of May, according to a screenshot of the email the blogger shared on X.

His final Reddit post, in May, was to the Kaczynski subreddit; he shared a video lambasting Chinese social-media culture. On X, his final posts, on July 8, revealed a disenchantment with both the Democratic and the Republican political parties and support for Robert F. Kennedy Jr. The previous month, he'd reposted another user's skepticism with doctors.

"My experience with the medical profession — and yours is probably similar — is that doctors are basically worthless unless you carefully manage them, and 2/3 of them are worthless even in that case," the post said.

Afterward, both accounts went dark.

Maronick, the family friend, told BI that there had "been some rumblings" that Mangione hadn't been in touch with his family in "quite some time."

In July, an apparent friend posted on X suggesting that Mangione hadn't responded to messages in months.

"You made commitments to me for my wedding and if you can't honor them I need to know so I can plan accordingly," the user wrote to Mangione. (The user could not be reached for comment.)

In recent months, one of Mangione's cousins began reaching out to Mangione's friends to ask whether anyone had heard from him, his high-school classmate told BI. The classmate texted Mangione but never heard back.

Mangione's mother filed a missing-persons report in San Francisco on November 18, writing that she hadn't seen her son since July, according to the San Francisco Standard. In a statement released on Monday, a group of Mangione's cousins wrote they were "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," the statement said.

Thompson was shot and killed on December 4 ahead of an annual investors meeting for UnitedHealth Group. Police say the bullet casings found on the scene had the words "delay," "deny," and "depose" written on them — which some have taken to be a reference to a book, "Delay, Deny, Defend," which details how insurance companies avoid paying medical bills.

Pennsylvania police, acting on a call from a McDonald's employee, found Mangione eating at a franchise location in Altoona. They say he had in his backpack a gun and a handwritten document expressing "ill will toward corporate America," with the phrase "these parasites had it coming."

Police arrested Mangione on forgery and gun charges. He is fighting extradition to New York, where he is expected to be charged with second-degree murder, a warrant obtained by BI shows. He has not formally entered a plea.

Thomas Dickey, an attorney representing Mangione, said in an interview on Tuesday that he had not seen "any evidence yet" that would implicate Mangione.

"I don't even know if this is him or whatever," he said. "So we're going to test those waters and give the government a chance to bring some evidence forward." Dickey did not immediately respond to a request for comment.

Mangione's high-school classmate said that nobody they knew recognized Mangione from the photos police released before his arrest. After law enforcement named Mangione as a suspect, though, "the eyebrows made sense," the classmate said.

At his initial court appearance Monday, a judge asked Mangione whether he was in touch with his family, multiple reports from outlets present at the arraignment said.

"Until recently," he responded.

Ana Altchek, Laura Italiano, and Natalie Musumeci contributed reporting.