Months before police identified Luigi Mangione as the man they suspect gunned down a top health insurance CEO and then seemingly vanished from Midtown Manhattan, another disappearing act worried his friends and family.

The 26-year-old scion of a wealthy Baltimore family who was a high school valedictorian and an Ivy League graduate, Mangione had maintained an active social media presence for years, posting smiling photos from his travels, sharing his weightlifting routine and discussing health challenges he faced.

He publicly kept track of nearly 300 books he had read or wanted to read, even posting a favorable review of the Unabomber manifesto on a book website.

But then, during the summer, Mangione appeared to stop posting online, prompting worried messages from some of his friends.

“Nobody has heard from you in months, and apparently your family is looking for you,” one user posted on X in October, tagging an account belonging to Mangione. “I don’t know if you are okay,” another posted.

Now, as police rush to piece together Mangione’s potential motive and movements leading up to last week’s shooting of UnitedHealthcare CEO Brian Thompson, those who know him are left wondering how someone with a promising life could have possibly committed such a brazen crime.

“I can make zero sense of it,” said R.J. Martin, who lived with Mangione at a Hawaii co-living space a few years ago, remembering him as friendly and thoughtful. “It’s unimaginable.”

A privileged upbringing

Mangione, who was arrested at a McDonald’s in Altoona, Pennsylvania, on Monday, made his first court appearance later that day. He was charged with forgery, carrying a firearm without a license, tampering with records or identification, possessing instruments of a crime and false identification to law enforcement authorities. He has not yet entered a plea and will be held without bail.

According to the criminal complaint against Mangione, he was carrying a backpack containing a black 3D-printed pistol and a black 3D-printed silencer. A police official told CNN he also had a handwritten document stating, “these parasites had it coming,” and expressing “ill will toward corporate America.”

Mangione himself, however, grew up in a wealthy Baltimore family that made it big in business. The suspect’s grandfather, Nicholas Mangione, a former masonry contractor who told the Baltimore Sun he started working at age 11, built a local real estate empire that included nursing home facilities around Maryland and two country clubs in the Baltimore suburbs.

The younger Mangione, who is one of more than 30 grandchildren of Nicholas Mangione and his wife, Mary, volunteered at a family business, the nursing home chain Lorien Health Systems, while he was in high school, according to his LinkedIn profile.

Mangione graduated from the prestigious Gilman School, an all-boys institution that is known as one of Baltimore’s toniest private schools, where he was the high school valedictorian in 2016.

In his valedictorian speech, Mangione lauded his classmates for “coming up with new ideas and challenging the world,” citing successful fundraisers and accomplishments in sports and academics.

“To the class of 2016, a kind of class that only comes around once every 50 years, it’s been an incredible journey, and I simply can’t imagine the last few years with any other group of guys,” he said.

Mangione attended the University of Pennsylvania, where he graduated in 2020 with a master’s and bachelor’s degree in computer science and a minor in mathematics, a university spokesperson told CNN. Mangione was a member of the Phi Kappa Psi fraternity, social media photos show.

In an interview for a university blog post, Mangione talked about how he had started a video game development club.

“In high school, I started playing a lot of independent games and stuff like that, but I wanted to make my own game, and so I learned how to code,” Mangione said. “In my freshman and sophomore years of high school, I learned (on my own) how to program, and that’s why I’m a computer science major now; that’s how I got into it… I just really wanted to make games.”

A former colleague of Mangione who worked with him as a counselor at a Stanford University summer program during his college years described him as outgoing and socially charming.

“I am flabbergasted,” the colleague said, asking not to be named because of the sensitivity of the news. “I never got the impression he would self-destruct.”

After graduating, Mangione worked as a software engineer for the online car sales company TrueCar, according to his LinkedIn page. His most recent address was in Hawaii, NYPD officials said.

Mangione is registered to vote at his family’s address in Cockeysville, Maryland, a Baltimore suburb, and is registered as unaffiliated with a political party, according to the state’s voter registration lookup website. He is the cousin of Maryland State Delegate Nino Mangione, a Republican, the state lawmaker’s office confirmed to local media.

The Mangione family also run a family foundation that has nearly $4.5 million in assets, and were longtime benefactors of Loyola University in Maryland, which named its aquatic center after them.

Private security guards were blocking access to the family’s house on a golf club Monday afternoon.

In a statement released by Nino Mangione’s office, the family said they are “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.

Health struggles

In recent years, Mangione suffered from troubling back pain and underwent surgery to treat it, according to a friend and online postings.

Around 2022, Mangione moved to Hawaii, where he lived for about six months at a co-working and co-living space in Honolulu, Martin told CNN. At the time, Mangione was working remotely, Martin said.

Mangione helped lead a book club for residents and liked going hiking and doing yoga, Martin, the founder of the co-living space, said. While residents sometimes discussed capitalism and the health care system, “it wasn’t like he had an ax to grind or he was even upset or angry about a particular issue,” Martin said. He didn’t remember Mangione ever talking about guns or violence.

Soon after Mangione moved to Hawaii, Martin said, Mangione did a surf lesson and ended up “in bed for about a week” with back pain. “It was really traumatic and difficult, you know, when you’re in your early twenties and you can’t, you know, do some basic things,” Martin said.

Martin said he fell out of touch with Mangione and last exchanged texts with him earlier this year. Mangione told him that he had undergone back surgery and sent him a photo of his X-ray that, Martin said, “looked heinous, with just giant screws going into his spine.”

Mangione posted a similar photo as the backdrop for his X page, which was taken offline after he was identified by police Monday.

And on the book review website, Goodreads, Mangione reported reading or wanting to read a number of books about coping with chronic back pain. He also linked to handwritten notes laying out his workout routine, which state that he was suffering from spondylolisthesis, the slippage of a vertebrae in the spine.

Posts from a now-deleted Reddit account that does not list Mangione’s name but closely matches many of his biographical details – including his university, age, major and health condition – say that the user had suffered from back aches related to spondylolisthesis since childhood but aggravated the condition after a surfing incident.

“My back and hips locked up after the accident,” the user wrote in July 2023, adding that “intermittent numbness has become constant” and “I’m terrified of the implications.”

A few weeks later, the user wrote that he had undergone spinal surgery, which improved his symptoms. The user did not appear to post about health insurance related to the surgery, or connect the treatment to UnitedHealthcare.

The user also detailed past struggles with health issues including Lyme disease and severe brain fog, which he said started after losing sleep during his fraternity’s “hell week” and caused his college grades to start “tanking.” He expressed frustration about how little was understood by the medical community about brain fog, writing that “it’s absolutely brutal to have such a life-halting issue… The people around you probably won’t understand your symptoms - they certainly don’t for me.”

Going silent

Mangione’s Goodreads profile also sheds more light on his thinking about political violence. Earlier this year, he reported having read the 1995 anti-technology manifesto written by the Unabomber, Ted Kaczynski, the infamous domestic terrorist and mathematician known for sending deadly bombs through the mail.

“It’s easy to quickly and thoughtless(ly) 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,” Mangione wrote in a review of the book in January. “He was a violent individual – rightfully imprisoned – who maimed innocent people. 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.”

In his review, Mangione also shared thoughts someone else had written about Kaczynski in a Reddit thread, quoting a commenter who had described his acts as “war and revolution,” saying that he “had the balls to recognize that peaceful protest has gotten us absolutely nowhere” and that “‘Violence never solved anything’ is a statement uttered by cowards and predators.”

In total, Mangione’s Goodreads profile listed him as reading or wanting to read nearly 300 books, including a book about mental illness, a biography of the creator of the atomic bomb and Michael Pollan’s popular book on the science of psychedelics.

On X, Mangione posted about science and technology, including artificial intelligence and psychedelics. The roughly 75 accounts he followed included prominent academics and public figures such as Joe Rogan, Edward Snowden, Robert F. Kennedy Jr. and the best-selling author of “The Anxious Generation,” a book about the negative effects of social media on American teens.

But Mangione doesn’t appear to have posted anything since midsummer – and posts addressed to his X account suggest that some of Mangione’s friends have been trying to get in touch with him.

In July, one user tweeted at Mangione, “I haven’t heard from you in months,” urging him to let him know if Mangione could honor the “commitments” he had made for the user’s wedding.

In late November, just weeks before the shooting, another user posted at Mangione, “thinking of you and prayers everyday in your name. Know you are missed and loved.”

CNN’s Curt Devine, Scott Glover, Rob Kuznia, Holmes Lybrand, and Daniel A. Medina contributed to this report.

Editor’s Note: This story was updated to include additional information about Mangione.